SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This report contains certain forward-looking statements within the meaning of
Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. All statements other than statements of historical fact may be forward-looking statements. You can identify these and other forward-looking statements by the use of words such as "may," "will," "could," "would," "should," "expects," "plans," "anticipates," "relies," "believes," "estimates," "predicts," "intends," "potential," "continue," "thinks," "seeks," or the negative of such terms, or other comparable terminology. Forward-looking statements also include the assumptions underlying or relating to any of the foregoing statements. Such forward-looking statements include, among others, forecasts of the future results of our operations; the percentage of spending that our customers allocate to process control; orders for our products and capital equipment generally; sales of semiconductors; the allocation of capital spending by our customers; growth of revenue in the semiconductor industry, the semiconductor capital equipment industry and our business; technological trends in the semiconductor industry; future developments or trends in the global capital and financial markets; the availability of the offer to repurchase our auction rate securities by the securities firm from which we purchased such securities; the future impact of the restatement of our historical financial statements, shareholder litigation and related matters arising from the discovery that we had retroactively priced stock options (primarily from July 1, 1997 to June 30, 2002) and had not accounted for them correctly; our future product offerings and product features; the success and market acceptance of new products; timing of shipment of backlog; the future of our product shipments and our product and service revenues; our future gross margins; our future selling, general and administrative expenses; our ability to successfully implement our efforts to reduce our operating costs, and the anticipated cost savings to be realized from such efforts; international sales and operations; our ability to maintain or improve our existing competitive position; success of our product offerings; creation and funding of programs for research and development; attraction and retention of employees; results of our investment in leading edge technologies; the effects of hedging transactions; the effect of the sale of trade receivables and promissory notes from customers; our future income tax rate; dividends; the completion of any acquisitions of third parties, or the technology or assets thereof; benefits received from any acquisitions and development of acquired technologies; sufficiency of our existing cash balance, investments and cash generated from operations to meet our operating and working capital requirements; and the adoption of new accounting pronouncements.

Our actual results may differ significantly from those projected in the forward-looking statements in this report. Factors that might cause or contribute to such differences include, but are not limited to, those discussed in Item 1A, "Risk Factors" in this report as well as in Item 1, "Business" and Item 7, "Management's Discussion and Analysis of Financial Condition and Results of Operations" in this report. You should carefully review these risks and also review the risks described in other documents we file from time to time with the Securities and Exchange Commission, including the Quarterly Reports on Form 10-Q that we will file during the remainder of the fiscal year ending June 30, 2010. You are cautioned not to place undue reliance on these forward-looking statements, and we expressly assume no obligation to update the forward-looking statements in this report after the date hereof.

CRITICAL ACCOUNTING ESTIMATES AND POLICIES

The preparation of our Condensed Consolidated Financial Statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions in applying our accounting policies that affect the reported amounts of assets, liabilities, revenues and expenses, and related disclosure of contingent assets and liabilities. Note 1 to the Consolidated Financial Statements in our Annual Report on Form 10-K for the fiscal year ended June 30, 2009 describes the significant accounting policies and methods used in preparation of the Consolidated Financial Statements. We based these estimates and assumptions on historical experience, and evaluate them on an on-going basis to ensure that they remain reasonable under current conditions. Actual results could differ from those estimates. We discuss the development and selection of the critical accounting estimates with the Audit Committee of our Board of Directors on a quarterly basis, and the Audit Committee has reviewed the Company's related disclosure in this Quarterly Report on Form 10-Q. The accounting policies that reflect our more significant estimates, judgments and assumptions and which we believe are the most critical to aid in fully understanding and evaluating our reported financial results include the following:

• Revenue Recognition

• Inventories

• Warranty

• Allowance for Doubtful Accounts

• Stock-Based Compensation

• Goodwill and Intangible Assets

• Income Taxes

System revenues recognized without a written acceptance from the customer were approximately 17%, 17% and 14% of total revenues for the three months ended September 30, 2009, June 30, 2009 and September 30, 2008, respectively. Shipping charges billed to customers are included in system revenues, and the related shipping costs are included in costs of revenues.

With the exception of the below paragraph that discusses the impact of Accounting Standards Codification on our critical accounting estimates and policies for fair value measurements, during the three months ended September 30, 2009 there were no significant changes in our critical accounting estimates and policies. Please refer to Management's Discussion and Analysis of Financial Condition and Results of Operations contained in Part II, Item 7 of our Annual Report on Form 10-K for our fiscal year ended June 30, 2009 for a more complete discussion of our critical accounting policies and estimates.

Adoption of fair value measurement

We adopted authoritative guidance for fair value measurements as of the beginning of fiscal year 2009. In February 2008, the Financial Accounting Standards Board ("FASB") issued a provision, which allows companies to elect a one-year delay in applying the fair value measurements guidance to certain fair value measurements, primarily related to nonfinancial assets and liabilities. The Company elected the delayed adoption date for its nonfinancial assets and liabilities impacted by the guidance. This guidance defines fair value, establishes a framework for measuring fair value under generally accepted accounting principles and enhances disclosures about fair value measurements. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The adoption of the guidance relating to the fair value measurement of nonfinancial assets and liabilities on July 1, 2009 did not have a material impact on our condensed consolidated results of operations or financial condition. See Note 2, "Fair Value Measurements," to the Condensed Consolidated Financial Statements.

Concurrently with the adoption of the fair value measurement and disclosure provisions, we adopted the authoritative guidance, which permits entities to elect, at specified election dates, to measure eligible financial instruments at fair value. See Note 2, "Fair Value Measurements," to the Condensed Consolidated Financial Statements.

Recent Accounting Pronouncements. In September 2009, the FASB's Emerging Issues Task Force ("EITF") issued authoritative guidance addressing revenue arrangements with multiple deliverables. The guidance requires revenue to be allocated to multiple elements using relative fair value based on vendor-specific-objective-evidence, third party evidence or estimated selling price. The residual method also becomes obsolete under this guidance. This guidance is effective for our interim reporting period ending on September 30, 2010. We are currently evaluating the impact of the implementation of this guidance on its financial position, results of operations and cash flows.

In September 2009, FASB's EITF issued authoritative guidance addressing certain revenue arrangements that include software elements. This guidance states that tangible products with hardware and software components that work together to deliver the product functionality are considered non-software products, and the accounting guidance under the revenue arrangements with multiple deliverables is to be followed. This guidance is effective for our interim reporting period ending on September 30, 2010. We are currently evaluating the impact of the implementation of this guidance on its financial position, results of operations and cash flows.

In August 2009, the FASB issued authoritative guidance for measuring liabilities at fair value that reaffirms the existing definition of fair value and reintroduces the concept of entry value into the determination of fair value of liabilities. Entry value is the amount an entity would receive to enter into an identical liability. The guidance is effective for our interim reporting period ending on December 31, 2009. We are currently evaluating the impact of the implementation on our financial position, results of operations and cash flows.

In June 2009, the FASB issued authoritative guidance for consolidations that changes how a company determines when an entity that is insufficiently capitalized or is not controlled through voting (or similar rights) should be consolidated. The determination of whether a company is required to consolidate an entity is based on, among other things, an entity's purpose and design and a company's ability to direct the activities of the entity that most significantly impact the entity's economic performance. This guidance is effective for our interim reporting period ending on September 30, 2010. We are currently evaluating the impact of the implementation on our financial position, results of operations and cash flows.

In June 2009, the FASB issued authoritative guidance to establish the FASB Accounting Standards Codification as the source of authoritative accounting principles and the framework for selecting the principles used in the preparation of financial statements of nongovernmental entities that are presented in conformity with generally accepted accounting principles in the United States. This guidance is effective for our interim reporting period ending on September 30, 2009 and only impacts references for accounting guidance.

In April 2009, the FASB issued authoritative guidance for business combinations that amends the provisions related to the initial recognition and measurement, subsequent measurement and disclosure of assets and liabilities arising from contingencies in a business combination. This guidance will require such contingencies be recognized at fair value on the acquisition date if fair value can be reasonably estimated during the allocation period. Otherwise, entities would typically account for the acquired contingencies in accordance with authoritative guidance for contingencies. The guidance became effective for our business combinations for which the acquisition date is on or after July 1, 2009. We did not complete any business combination during the three months ended September 30, 2009, and the effect on future periods will depend on the nature and significance of business combinations subject to this guidance.

In April 2009, the FASB issued authoritative guidance to increase the frequency of fair value disclosures of financial instruments, thereby enhancing consistency in financial reporting. The guidance relates to fair value disclosures for any financial instruments that are not currently reflected on a company's balance sheet at fair value. Prior to the effective date of this guidance, fair values for these assets and liabilities have only been disclosed once a year. The guidance requires these disclosures on a quarterly basis, providing qualitative and quantitative information about fair value estimates for all those financial instruments not measured on the balance sheet at fair value. The disclosure requirement under this guidance is effective for our interim reporting period ended on September 30, 2009. The implementation did not have a material impact on our financial position, results of operations or cash flows as it is disclosure-only in nature.

In December 2008, the FASB issued authoritative guidance for an employer's disclosures about plan assets of a defined benefit pension or other postretirement plan. The guidance requires annual disclosures surrounding how investment allocation decisions are made, including the factors that are pertinent to an understanding of investment policies and strategies. The annual disclosure requirement under this guidance is effective for our fiscal year beginning July 1, 2009. The guidance does not change the accounting treatment for postretirement benefit plans.

On August 27, 2008, the U.S. Securities and Exchange Commission ("SEC") announced that they will issue for comment a proposed roadmap regarding the potential use by U.S. issuers of financial statements prepared in accordance with International Financial Reporting Standards ("IFRS"). IFRS is a comprehensive series of accounting standards published by the International Accounting Standards Board. Under the proposed roadmap, we could be required in fiscal year 2014 to prepare financial statements in accordance with IFRS, and the SEC will make a determination in 2011 regarding the mandatory adoption of IFRS. We are currently assessing the impact that this potential change would have on our consolidated financial statements, and we will continue to monitor the development of the potential implementation of IFRS.

In April 2008, the FASB issued authoritative guidance for general intangibles other than goodwill, amending the factors that should be considered in developing renewal or extension assumptions used to determine the useful life of a recognized intangible asset. This guidance is effective for intangible assets acquired on or after July 1, 2009. The adoption did not have a material impact on our financial position, results of operations or cash flows.

EXECUTIVE SUMMARY

KLA-Tencor Corporation is a leading supplier of process control and yield management solutions for the semiconductor and related nanoelectronics industries. Within our primary area of focus, our comprehensive portfolio of products, services, software and expertise helps integrated circuit ("IC" or "chip") manufacturers manage yield throughout the entire wafer fabrication process - from research and development to final volume production. In addition to the semiconductor industry, our technologies serve a number of other industries, including light emitting diode ("LED"), data storage, solar process development and control, and general materials research.

Our products and services are used by virtually every major wafer, IC and photomask manufacturer in the world. Our revenues are driven largely by capital spending by our customers who operate in one or more of several key semiconductor markets, including the memory, foundry and logic markets. Our customers purchase our products either in response to the need to drive advances in process technologies or to ramp up production to satisfy demand from industries such as communication, data processing, consumer electronics, automotive and aerospace. We believe that, over the long-term, our customers will continue to invest in advanced technologies and new materials to enable smaller design rules and higher density applications, as well as reduced cost, which in turn will drive increased adoption of process control to reduce defectivity.

As a supplier to the global semiconductor and semiconductor-related industries, we are subject to business cycles, the timing, length and volatility of which can be difficult to predict. The industries we serve have historically been cyclical due to sudden changes in demand and manufacturing capacity. We expect our customers' technology-related capital spending on process control (as differentiated from capacity-related capital spending) to increase over the long term, as technology spending is driven by the demand

for more precise diagnostics capabilities to address multiple new defects as a result of further shrinking of device feature sizes, the transition to new materials, new devices and circuit architecture, new lithography challenges and fab process innovation. However, our ability to predict future capacity-related capital spending by our customers is more limited, as such spending is more closely connected to the unpredictable business cycles within their industries.

The demand for our products is generally affected by the profitability of our customers, which is driven by capacity and market supply for their products. While semiconductor content in communication, data processing, consumer electronics, automotive and aerospace products continues to increase, the global economic weakness during the fiscal year ended June 30, 2009 adversely impacted our customers that operate in those industries and consequently impacted the demand for our products. However, over the past two quarters, the outlook for economic growth, end product demand for our customer's products and factory utilization of our customers has improved, resulting in an increased in the demand for semiconductor capital equipment. As our foundry customers accelerate capital investments, we have started to increase production volumes to support anticipated customer demand. We cannot predict the duration and sustainability of the improving business conditions, and whether the increased demand that we are experiencing from some of our foundry customers will translate to increased demand from the memory and logic customers. As we increase production volumes and make commitments to increase our capacity in anticipation of improved business conditions, we remain at risk of incurring inventory related and other restructuring charges if the improved business conditions do not sustain.

The following table sets forth some of the key quarterly unaudited financial information which we use to manage our business.

                                       Fiscal year 2010                      Fiscal year 2009
(In thousands, except net income per         First           First       Second          Third         Fourth
share - diluted)                            Quarter         Quarter     Quarter         Quarter        Quarter
Total revenues                         $         342,687   $ 532,513   $  396,589      $ 309,612      $ 281,502
Total costs and operating expenses     $         327,737   $ 497,575   $  902,220      $ 381,893      $ 316,469
Income (loss) from operations          $          14,950   $  34,938   $ (505,631 )    $ (72,281 )    $ (34,967 )
Net income (loss)                      $          20,405   $  19,289   $ (434,254 )    $ (82,827 )    $ (25,576 )
Net income (loss) per share:
Basic (1)                              $            0.12   $    0.11   $    (2.57 )    $   (0.49 )    $   (0.15 )
Diluted (1)                            $            0.12   $    0.11   $    (2.57 )    $   (0.49 )    $   (0.15 )

(1) Basic and diluted earnings per share are computed independently for each of the quarters presented based on the weighted average basic and fully diluted shares outstanding for each quarter. Therefore, the sum of quarterly basic and diluted per share information may not equal annual basic and diluted earnings per share.

RESULTS OF OPERATIONS

Revenues and Gross Margin



                                                               Three months ended
                                               September 30,        June 30,         September 30,           Q1 FY10 vs.               Q1 FY10 vs.
(Dollar amounts in thousands)                      2009               2009               2008                  Q4 FY09                   Q1 FY09
Revenues:
Product                                       $       229,251       $ 176,226       $       405,496       $ 53,025        30 %     $ (176,245 )     -43 %
Service                                       $       113,436       $ 105,276       $       127,017       $  8,160         8 %     $  (13,581 )     -11 %

Total revenues                                $       342,687       $ 281,502       $       532,513       $ 61,185        22 %     $ (189,826 )     -36 %

Costs of revenues                             $       171,892       $ 164,621       $       252,813       $  7,271         4 %     $  (80,921 )     -32 %
Stock-based compensation expense included
in costs of revenues                          $         3,288       $   5,091       $         5,456       $ (1,803 )     -35 %     $   (2,168 )     -40 %
Gross margin percentage                                    50 %            42 %                  52 %

Product revenues

Product revenues increased by 30% during the three months ended September 30, 2009 from the three months ended June 30, 2009 as our customers accelerated their capital spending due to improved factory utilization and demand for their products, as well as increased demand from our customers for inspection and measurement equipment to support their advanced technology development programs. These factors contributed to an increase in the number of tools that we sold within each of our major product lines, as evidenced by the fact that, from the three months ended June 30, 2009 to the three months ended September 30, 2009, revenues from sales of defect inspection equipment increased by 30% while metrology equipment sales revenue increased by 13%.

Product revenues decreased by 43% during the three months ended September 30, 2009 from the three months ended September 30, 2008 as a result of a reduction in capital spending by our customers due to the weakness in the semiconductor industry and a deteriorating macroeconomic environment. These factors contributed to a significant decline in the number of tools that we sold within each of our major product lines, as evidenced by the fact that, from the three months ended September 30, 2008 to the three months ended September 30, 2009, revenues from sales of defect inspection equipment declined by 43% while metrology equipment sales revenues fell by 47%. The decrease in the quantity of tools sold that we experienced during the three months ended September 30, 2009, as compared to the three months ended September 30, 2008, was a function of a number of converging factors in our industry and in the macroeconomic environment. These factors included customers delaying capital investments (including purchases and installations of our products) and otherwise reducing capital spending in an effort to conserve cash in response to their business environment, even as their need for more precise diagnostics capabilities increases with technological advances, as well as customers having reduced access to the capital necessary to fund investments in new equipment due to the weak macroeconomic and credit environments during three months ended September 30, 2009. Our product revenues may continue to be adversely affected by various factors, such as global economic conditions.

Service revenues

Service revenues are generated from maintenance service contracts, as well as time and material billable service calls made to our customers after the expiration of the warranty period. The amount of service revenues generated is generally a function of the number of post-warranty systems installed at our customers' sites and the utilization of those systems. Service revenues increased in the three months ended September 30, 2009 compared to the three months ended June 30, 2009 as a result of our customers reactivating some of the previously idled production equipment in response to increased factory utilization and increased demand for our customers products. Service revenue decreased during the three months ended September 30, 2009 from the three months ended September 30, 2008 as customers had idled their under-utilized production equipment in response to the recent weakness in the semiconductor industry and a deteriorating macroeconomic environment which adversely impacted the demand for our customers products.

Revenues by region

Revenues by region for the periods indicated were as follows:

                                                          Three months ended
(Dollar amounts in thousands)    September 30, 2009         June 30, 2009         September 30, 2008
United States                   $       74,557     22 %    $   85,562    30 %    $       90,554     17 %
Taiwan                                 122,119     36 %        40,607    15 %            85,518     16 %
Japan                                   59,352     17 %        73,251    26 %           169,907     32 %
Europe & Israel                         23,925      7 %        36,430    13 %            43,427      8 %
Korea                                   29,512      8 %        17,176     6 %            87,861     16 %
Rest of Asia Pacific                    33,222     10 %        28,476    10 %            55,246     11 %

Total                           $      342,687    100 %    $  281,502   100 %    $      532,513    100 %

A significant portion of our revenues continue to be generated in Asia, where a substantial portion of the world's semiconductor manufacturing capacity is located, and we expect that this trend will continue.

Gross margin

Our gross margin fluctuates with revenue levels and product mix, and is affected by variations in costs related to manufacturing and servicing our products. Our gross margin percentage was higher during the three months ended September 30, 2009 compared to the three months ended June 30, 2009 primarily due to higher product and service revenues, increased manufacturing capacity utilization, and lower intangible assets amortization expense. The following are expenses that were recorded in costs of revenues in the three months ended September 30, 2009 compared to the three months ended June 30, 2009:

• $59.1 million for employee-related expenses, compared to $60.3 million in the three months ended June 30, 2009, and

• $4.9 million charge for excess inventory write-downs, compared to $14.9 million in the three months ended June 30, 2009.

Our gross margin percentage was lower during the three months ended September 30, 2009 compared to the three months ended September 30, 2008 primarily due to lower product and service revenues and lower manufacturing capacity utilization. The following are expenses that were recorded in costs of revenues in the three months ended September 30, 2009 compared to the three months ended September 30, 2008: . . .