how many congressional seats are up for reelection every two years?
Congress, made up of the 435 House and the 100 Senate seats, has two different election cycles. House seats are up for re-election every two years during even numbered years, and Senate seats are re-elected every six years. There are 469 seats in the U.S. Congress that are up for the 2016 election â 34 Senate seats and 435 House seats. On your ballot, there are options for a U.S. Senator and for U.S. Representative.