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 — 34 Senate seats and 435 House seats. On your ballot, there are options for a U.S. Senator and for U.S. Representative.