The 45 countries represented on the interim commission were entitled to original membership. The Russian Federation retains the entitlement to original membership previously held by the USSR, to be made effective at any time through the ratification of FAO's constitution.
Any nation may withdraw after four years. Among the countries that have withdrawn and later rejoined are Czechoslovakia (withdrew 1950, rejoined 1969), Poland (withdrew 1951, rejoined 1957), Hungary (withdrew 1952, rejoined 1967), and South Africa (withdrew 1964, rejoined 1993). Taiwan withdrew in 1952.
As of November 2001, FAO had 183 member nations. In addition, Puerto Rico was an associate member. The European Union was a member organization.