The 2010 midterm election will be held on Tuesday, November 2 with at least 36 of the 100 seats in the Senate being contested and all House seats coming up for election.
The U.S. Senate
The current make-up of the U.S. Senate is 58 Democrats, 40 Republicans, and two Independents. A temporary appointment currently holds the seat of Massachusetts Senator Ted Kennedy following his death in 2009. On January 19, 2010, there will be a special election to fill the seat.

If Democrats lose a net of ten or more seats or caucus members in 2010, they'll lose U.S. Senate control.

As of October 24, 2010, five Senate races remain toss-ups per polling: Colorado, Nevada, Illinois, Pennsylvania, and West Virginia, all seats now held by Democrats.

Senate seats in Arkansas, Indiana and North Dakota are expected to change from Democratic to Republican.

Three other Senate seats now held by Democrats remain in close races and could be lost to Republicans: California, Washington, Wisconsin. Barbara Boxer in California and Patty Murray of Washington are presently leading in the polls, though.

Elections to the United States Senate will be held on November 2, 2010, for at least 36 of the 100 seats in the United States Senate.

Thirty-four of the seats are for six-year terms, beginning January 3, 2011. They will join Senate Class III, which traces its roots back to the Senators who served full six-year terms from March 4, 1789 to March 3, 1795.

The Senate is currently composed of 58 Democrats, 40 Republicans, and two independents who caucus with the Democrats. Of the seats expected to be up for election in 2010, 19 are held by Democrats and 18 are held by Republicans.

The current make-up of the U.S. Senate is 58 Democrats, 40 Republicans, and two Independents. A temporary appointment currently holds the seat of Massachusetts Senator Ted Kennedy following his death in 2009. On January 19, 2010, there will be a special election to fill the seat.

The U.S. House of Representatives

The current make-up of the U.S. House of Representatives is 256 Democrats, 178 Republicans and one vacancy. All members of the House will face re-election in 2010. While it is unlikely that the Democratic Party will lose control of the House in 2010, historically the party that wins the White House loses seats in the following midterm elections. This, combined with the fact that Democrats currently hold a substantial majority in House, points to a likelihood that the Democrats will lose a large number of seats in the 2010.