|U.S. Senator from Colorado|
From: January 3, 2009 – Present
|Successor||Incumbent (no successor)|
|U.S. Representative from Colorado's 1st District|
From: January 3, 1999 – January 3, 2009
|Spouse(s)||Maggie L. Fox|
Mark Emery Udall (born July 18, 1950) is the senior United States Senator from Colorado and a member of the Democratic Party. He has voted with a majority of his Democratic colleagues 91.8% of the time during the current Congress.  Udall serves on the Committee on Armed Services and the Committee on Energy and Natural Resources.
Previously Udall was a five term U.S. Representatives from Colorado's 2nd congressional district, which represents the city of Boulder and the northwestern suburbs of Denver. He is the cousin of New Mexico Senator Tom Udall, a Democrat, and the second cousin of former Oregon Senator Gordon Smith, a Republican.
According to National Journal, Udall is one of the two most liberal Senators.