The 110th United States Congress was a meeting of the legislative branch of the United States federal government, between January 3, 2007, and January 3, 2009, during the last two years of the Presidency of George W. Bush. It was composed of the Senate and the House of Representatives. The apportionment of seats in the House was based on the 2000 U.S. Census.The Democratic Party won a majority in both chambers, giving them full control of Congress for the first time since the 103rd Congress in 1993, which was also the last time they controlled the House.

Officially in the Senate, there were 49 Democrats, 49 Republicans, and two independents, but because both of the independents caucused with the Democrats, this gave the Democrats an operational majority. No Democratic-held seats had fallen to the Republican Party in the 2006 elections.Democrat Nancy Pelosi became the first female Speaker of the House. The House also received the first Muslim (Keith Ellison) and Buddhist (Hank Johnson and Mazie Hirono) members of Congress.