Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

On November 19, 2012, Sigma-Aldrich Corporation (the "Company") announced an organizational realignment effective January 1, 2013. Pursuant to the realignment, the Company's Research business will be divided into two new business units - Applied Markets and Research Markets. Franklin D. Wicks, Executive Vice President and President, Research, will become President of the Applied Markets Business Unit. Dr. Wicks will remain an Executive Vice President of the Company. Eric M. Green, Vice President and Managing Director, International, will become President of the Research Markets Business Unit. Gilles A. Cottier, Executive Vice President and President, SAFC, will continue to lead the SAFC business, which will be renamed the SAFC Commercial Markets Business Unit.

For additional information regarding the organizational realignment, please see the corresponding press release announcing it. A copy of the press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference.

Item 9.01 Financial Statements and Exhibits.

Exhibit No. Description
99.1 Text of press release dated November 19, 2012.

---