As of December 30, 2019, 2,164 major party candidates have filed with the Federal Elections Commission (FEC) to run for the U.S. Senate and House of Representatives in 2020.

So far, 319 candidates are filed to run for Senate. Of those, 272—143 Democrats and 129 Republicans—are from one of the two major political parties. In 2018, 527 candidates filed with the FEC to run for U.S. Senate, including 137 Democrats and 240 Republicans.

For U.S. House, 2,028 candidates are filed with the FEC to run in 2020. Of those, 1,892—935 Democrats and 957 Republicans—are from one of the two major political parties. In 2018, 3,244 candidates filed with the FEC, including 1,566 Democrats and 1,155 Republicans.

There were no retirement announcements from members of Congress in the past week. To date, four senators (three Republicans and one Democrat) and 34 representatives (25 Republicans and nine Democrats) are not running for re-election. In 2018, 55 total members of Congress—18 Democrats and 37 Republicans—did not seek re-election.

On November 3, 2020, 35 Senate seats and all 435 House seats are up for election. Of those Senate seats, 33 are regularly scheduled elections, while the other two are special elections in Arizona and Georgia. Twelve are Democratic-held seats and 23 are Republican-held seats. In the House, where all seats are up for election, Democrats currently hold a majority with 233 seats.

Additional Reading:
United States Senate elections, 2020
United States House of Representatives election, 2020
List of U.S. Congress incumbents who are not running for re-election in 2020