Elections were held in Maryland on Tuesday, November 2, 2010. Primary elections were held on September 14, 2010.
 Incumbent Democratic Senator Barbara Mikulski ran for re-election against Republican Eric Wargotz and many third-party and independent candidates. She previously won senate elections in 1986, 1992, 1998, and 2004 by margins of 21, 42, 41 and 31 percentage points, respectively. She won the Democratic primary with token opposition and defeated Republican Eric Wargotz 62%-38%. With her victory and service to the end of her term in January 2017, Mikulski tied Paul Sarbanes as the longest-serving senator in state history, and also becoming the longest-serving female senator in history.
 All eight of Maryland's seats in the United States House of Representatives were up for election in 2010. As of 2021, this is the last time that Republicans won more than one congressional district in Maryland.
 Results of the 2010 United States House of Representatives elections in Maryland by district:
 Incumbent Democrat Frank Kratovil ran for re-election against state senator Andy Harris (politician) and Libertarian Richard Davis. Harris defeated Kratovil and Davis, 54%-42%-4%.
 Incumbent Democrat Dutch Ruppersberger ran for re-election against Republican Marcelo Cardarelli, a physician. He won 64%-33%.
 Incumbent Democrat John Sarbanes, son of former senator Paul Sarbanes, ran against Republican Jim Wilhelm. He defeated him, 61%-36%.
 Incumbent Democrat Donna Edwards ran for re-election against Republican Robert Broadus and won in a landslide, 83%-16%.
 Incumbent Democrat and House Majority Leader Steny Hoyer ran for re-election. He has represented this district since 1981. He was challenged by Republican Charles Lollar, the Chairman of the Charles County Republican Party. He won 64%-35%.
 Incumbent Republican Roscoe Bartlett ran for re-election against Democrat Andrew Duck. Bartlett was re-elected with 61% of the vote to Duck's 33%. This would be the last time a Republican would represent the 6th District, as well as the last time any Republican other than Andy Harris won a federal election in Maryland. Bartlett's district would be redrawn after the 2010 United States redistricting cycle. The composition of the district changed drastically, and he lost to John Delaney (Maryland politician).
 Incumbent Democrat Elijah Cummings ran for re-election, having represented the district since 1996. He defeated Republican Frank Mirabile 75%-23%.
 Incumbent Democrat Chris Van Hollen ran for re-election, having represented the district since 2003. He defeated Michael Lee Philips 73%-25%. 
 Incumbent Democratic Governor Martin O'Malley ran for re-election against Republican challenger and former Governor Robert Ehrlich, as well as many third-party and independent candidates. Ehrlich had previously lost reelection to O'Malley in 2006. O'Malley defeated Ehrlich on election day, 56%-42%, a wider margin than his 53%-46% victory over incumbent Ehrlich. O'Malley and Brown became the first gubernatorial ticket in Maryland history to receive more than one million votes.
 Democratic incumbent Peter Franchot ran for re-election against Republican challenger William Henry Campbell. Franchot defeated Campbell, 61%-39%.
 Democratic incumbent Douglas Gansler ran unopposed for re-election. He received all but 1.82% of votes in the general election, to write-in candidates.
 All forty-seven seats of the Maryland Senate were up for election in 2010. Democrats entered the election with a 33-14 supermajority. They maintained this supermajority, winning an additional two seats.
 All 141 seats in the Maryland House of Delegates were up for election in 2010. Democrats entered the election with a 104-37 supermajority. They lost six seats in the election.
 Multiple judicial positions were up for election in 2010.
 Three measures were certified for the 2010 ballot.
 Many elections for county and city offices were also held on November 2, 2010.