Under the provisions of the New York Constitution of 1938, re-apportioned in 1953, 58 Senators and 150 assembly members were elected in single-seat districts for two-year terms.

In 1964, the U.S. Supreme Court handed down several decisions establishing that State legislatures should follow the One man, one vote rule to apportion their election districts.

Senators John H. Hughes and Lawrence M. Rulison (both Rep.) questioned the authority of the federal court to shorten the term of the 1964 electees,[1] alleging excessive costs for the additional election in an off-year.

The lame-duck Legislature of 1964 met for a special session at the State Capitol in Albany from December 15 to 31, 1964, to re-apportion the legislative districts for the election in November 1965, gerrymandering the districts according to the wishes of the Republican majority before the Democrats would take over the Legislature in January.

3 of the 4 women members of the previous legislature State Senator Constance Baker Motley, a lawyer of Manhattan; and Assembly Members Constance E. Cook (Republican), a lawyer of Ithaca, and Aileen B. Ryan (Democrat), a former school teacher of the Bronx—were re-elected.

The Legislature met for the regular session (the 188th) at the State Capitol in Albany on January 6, 1965;[5] and adjourned on June 23.

The court also held that, although the constitutional State Senate apportionment formula provides for additional seats, the increase from 58 to 65 was unwarranted.

Bernard G. Gordon, Robert Watson Pomeroy, William S. Calli and Kenneth R. Willard changed from the Assembly to the Senate.