Summary of ZENITH NATIONAL INSURANCE CORP

Item 5.03 Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year.

On May 13, 2009, the Board of Directors of Zenith National Insurance Corp., the Registrant, adopted Amended and Restated Bylaws of the Registrant. The following summarizes the changes that were made through the amendment and restatement (other formatting changes were also made):

Bylaws Provision                                         Revisions
Article II                                Addition of provisions requiring
                                          advance notice of stockholder proposals
                                          to be given to the Registrant between
                                          120 and 45 days before the date of the
                                          applicable stockholder meeting

Article II, Section 1                     Addition of electronic stockholder
                                          meeting procedures

Article II, Section 7                     Addition of cross reference of voting
                                          procedures to Certificate of
                                          Incorporation, which provides for
                                          cumulative voting; and clarification
                                          that stock ledger governs who is
                                          entitled to vote at stockholder
                                          meetings

Article II, Section 10                    Addition of description of conduct of
                                          stockholder meetings

Article II, Section 11                    Addition of description of inspectors
                                          of election at stockholder meetings

Article III, Section 2                    Addition of description of quorum of
                                          directors for meetings of Board
                                          committees

Article III, Section 4                    Clarification of duration of term of
                                          office for officers

Article III, Section 6                    Clarification of contents and methods
                                          of providing notice of special meetings
                                          of the Board

Article III, Section 8                    Addition of actions to be taken by
                                          directors without a meeting to be
                                          accomplished by electronic transmission

Article III, Section 9                    Addition of telephonic Board meetings

Article III, Section 12                   Deletion of section providing for
                                          indemnification of directors, officers
                                          and employees since it is already
                                          provided for in the Registrant's
                                          Certificate of Incorporation

Article IV Modification of description of Board committees to reflect stock exchange rules and current committee charters

Article V, Section 1 Clarification of Board's ability to remove officers and fill vacancies

Article V, Section 7 Addition of Board's ability to authorize Chairman or President to appoint officers

Article VI, Section 2 Clarification of manner that director, officer or committee vacancies may be filled

Article VIII, Section 5 Addition of electronic notice to directors, committee members or stockholders; addition of electronic waiver of notice of meeting; and clarification of waiver of notice by attendance at meeting

The foregoing description of the amendments to the Bylaws is qualified in its entirety by reference to the full text of the Registrant's Amended and Restated Bylaws attached to this Current Report on Form 8-K as Exhibit 3.2 and incorporated herein by this reference.