The apportionment of seats in the House of Representatives was based on the 1950 United States census.

The Democratic Party won back majorities in both the House and Senate, thus giving them full control of Congress, although Republican Party briefly won the Senate after the last Congressional session.

The count below identifies party affiliations at the beginning of the first session of this Congress, and includes members from vacancies and newly admitted states, when they were first seated.

Senators are popularly elected statewide every two years, with one-third beginning new six-year terms with each Congress.

Preceding the names in the list below are Senate class numbers, which indicate the cycle of their election.