Final authority in administration of the Union lies with the General Assembly exercised collectively by delegates of National Committees (See Stautes B18) of the Member Societies and members of the Executive Board.

The General Assembly ordinarily meets at least every three years on the occasion of an International Congress organized under auspices of the Union, convening at least once during each meeting.

The General Assembly elects the Officers of the Union (the President-Elect, two Vice-Presidents, Secretary-General, and Treasurer) and two Members-at-Large, receives reports and, as required, approves activities of the Executive Board and initiates further business.

The General Assembly may direct the Executive Board to establish any Division or other working group deemed necessary for the administrative or scientific work of the Union.

The IUMS General Assembly met the last time on Sunday August 10 2008 in Istanbul and will meet again during the IUMS congresses in Sapporo in 2011.