The Communist Party of the Soviet Union (Коммунисти́ческая Па́ртия Сове́тского Сою́за = КПСС) was the name used by the successors of the Bolshevik faction of the Russian Social Democratic Labour Party from 1952 to 1991, but the wording Communist Party was present in the party's name since 1918.

The party had split into two factions, the Bolsheviks and the Mensheviks, primarily over the issue of party membership. Bolsheviks favored a closed membership of strictly full time professional revolutionaries; whereas the Mensheviks favored open party membership. The Bolsheviks seized power in October of 1917 (by the Julian calendar still in use in Russia at that time). Soon after, they banned the Mensheviks (and all other opposition political organizations) and in 1918 the 7th Party Congress changed their own name to the All-Russian Communist Party (Bolsheviks). In 1925, the 14th Party Congress changed the name to the All-Union Communist Party (Bolsheviks) . The name Communist Party of the Soviet Union was accepted in 1952 at the 19th Party Congress.

A name change had been first mooted in Lenin's April Theses, which articulated Lenin's sense that the term Social-Democracy had become devalued, a notion he articulated in his pamphlet Socialism and War (1915) where he talked of the pro-war Social-Democrats as Social-Chauvinists.

The Marxist-Leninist structure of the CPSU was copied by many other Communist parties (c.f.).

In February of 1990, the CPSU called for the end of its constitutional guarantee of power. In March, the Congress of Peoples Deputies repealed Article Six of the Soviet Constitution, which had guaranteed monopoly political power for the party.

Following the August coup in 1991, the CPSU was banned by Boris Yeltsin on all Russian soil. The KGB was disbanded as were other CPSU-related agencies and organisations. Yeltsin's action was later declared unconstitutional but by this time the USSR had ceased to exist.

After the collapse of the Soviet Union, the organization became known as the Communist Party of the Russian Federation.