The Soviet of the Union (Russian: Сове́т Сою́за, Sovet Soyuza) was the lower chamber of the Supreme Soviet of the Union of Soviet Socialist Republics, elected on the basis of universal, equal and direct suffrage in accordance with the principles of Soviet democracy, and with the rule that each deputy would represent the same number of voters. Under the 1936 Soviet Constitution, there was one deputy for every 300,000 people; this was changed by the 1977 Soviet Constitution, which provided that both chambers would have an equal number of members. Although the party gave general guidelines on nominations, such as the ratio of the social composition of the nominees, much of the work was left to local bodies and people's representatives. As opposed to the upper chamber, the Soviet of Nationalities, the Soviet of the Union represented the interests of all of the people of the Soviet Union no matter what their nationality was.
The Soviet of the Union had the same rights and competence as the Soviet of Nationalities, including the right for legislative initiative. In practice, until 1989, it did little more than approve decisions already made by the top leadership of the Communist Party of the Soviet Union. After the 1989 elections the Soviet of the Union acquired a much greater role, and was the scene of many lively debates.