The 1977 Constitution of the Soviet Union, officially the Constitution (Fundamental Law) of the Union of Soviet Socialist Republics,[a] was the constitution of the Soviet Union adopted on 7 October 1977.

Constitution of the Soviet Union (1977)
The 1977 Constitution, also known as the Brezhnev Constitution or the constitution of the developed Socialism, was the third and final constitution of the Soviet Union, adopted unanimously at the 7th (Special) Session of the Ninth Convocation of the Supreme Soviet and signed by Chairman of the Presidium Leonid Brezhnev. The 1977 Constitution replaced the 1936 Constitution and the Soviet public holiday of USSR Constitution Day was shifted from 5 December to 7 October. October 7 - USSR Constitution Day was a holiday and not a working day