The 2010 United States Senate election in Indiana took place on November 2, 2010, alongside 33 other elections to the United States Senate in other states and elections to the United States House of Representatives and various state and local elections to fill Indiana's class III United States Senate seat. Incumbent Democratic Senator Evan Bayh decided in February 2010 to retire instead of seeking a third term shortly after Dan Coats announced his candidacy. Bayh's announcement came one day before the filing deadline and no Democratic candidate submitted enough signatures by the deadline to run, so the State Democratic Party chose U.S. Congressman Brad Ellsworth as their nominee. The Libertarian Party nominated YMCA instructor Rebecca Sink-Burris, who had previously unsuccessfully run for this seat in 1998. Coats won the open seat, having previously held it from 1989 to 1999. Bayh later unsuccessfully ran for this seat again in 2016.

Democratic nomination

Senate candidates in Indiana were required to have submitted 500 signatures from each of the state's nine congressional districts by February 16, 2010, one day after Bayh announced his retirement. Democratic leaders thought the popular incumbent would run for reelection, and as a result, no Democratic candidate had submitted the requisite signatures by the deadline to run in the state's primary, meaning that the Indiana Democratic Party's executive committee chose the party's nominee. U.S. congressman Brad Ellsworth was officially selected on May 15.

Republican primary

Candidates

Debates

Endorsements

Coats

Hostettler

Stutzman

Polling

Results

[[File:Indiana U.S. Senate Republican primary, 2010.svg|thumb|170px|Results by county: Coats {{legend|#cc2f4a|60–70%}} {{legend|#e27f90|50–60%}} {{legend|#f2b3be|40–50%}} {{legend|#ffccd0|<40%}} Stutzman {{legend|#ffccaa|<40%}} {{legend|#ffb380|40–50%}} {{legend|#ff9955|50–60%}} {{legend|#ff7f2a|60–70%}} Hostettler {{legend|#afe9af|30–40%}} {{legend|#87de87|40–50%}} {{legend|#5fd35f|50–60%}} {{legend|#37c837|60–70%}} {{legend|#2ca02c|70–80%}} ]]

General election

Candidates

Campaign

After Coats' win in the Republican primary, Ellsworth began to heavily criticize Coats for his ties to lobbyists. He called for more disclosure of the meetings lawmakers have with lobbyists, banning congressional staff from lobbying for six years after their congressional jobs, requiring Congress members to put all their investments in blind trusts, more disclosure of Senate candidates' personal financial information, and changes to the U.S. Senate filibuster rules. He proposed lowering number of votes required to break a filibuster to 55 from the current 60. In response to Ellsworth's charges, Coats published his lobbying record in an 815-page document. Coats emphasized the individual issues rather than ethic reforms advocated by his opponent. He focused on Ellsworth's record of voting in support of the Economic Stimulus Act of 2008, cap and trade legislation, and health care bill. Coats opinion of the healthcare law was that "the only responsible solution ... is to repeal the Obama-Pelosi-Ellsworth health spending bill and quickly replace it with cost-effective, incremental pieces that will decrease costs, increase coverage and not break the bank."

Debates

The three candidates took part in three televised debates.

Predictions

Polling

Fundraising

Results

Counties that flipped from Democratic to Republican

• Delaware (largest city: Muncie) • Porter (largest city: Portage) • Madison (largest city: Anderson) • Spencer (largest city: Santa Claus) • Starke (largest city: Knox) • Tippecanoe (largest city: Lafayette) • Vanderburgh (largest city: Evansville) • Scott (Largest city: Scottsburg) • Blackford (Largest city: Hartford City) • Clark (Largest city: Jeffersonville) • Crawford (Largest city: Marengo) • Floyd (Largest city: New Albany) • Gibson (Largest city: Princeton) • Jefferson (Largest city: Madison) • Knox (Largest city: Vincennes) • Pike (Largest city: Petersburg) • Posey (Largest city: Mount Vernon) • Switzerland (Largest city: Vevay) • Warrick (Largest city: Boonville) • Adams (Largest city: Decatur) • Allen (Largest city: Fort Wayne) • Bartholomew (Largest city: Columbus) • Benton (Largest city: Fowler) • Brown (Largest city: Nashville) • Carroll (Largest city: Delphi) • Cass (Largest city: Logansport) • Clay (Largest city: Brazil) • Clinton (Largest city: Frankfort) • Daviess (Largest city: Washington) • Decatur (Largest city: Greensburg) • DeKalb (Largest city: Auburn) • Dubois (Largest city: Jasper) • Elkhart (Largest city: Elkhart) • Fayette (Largest city: Connersville) • Fountain (Largest city: Attica) • Franklin (Largest city: Brookville) • Fulton (Largest city: Rochester) • Grant (Largest city: Marion) • Greene (Largest city: Linton) • Hancock (Largest city: Greenfield) • Harrison (Largest city: Corydon) • Henry (Largest city: New Castle) • Howard (Largest city: Kokomo) • Huntington (Largest city: Huntington) • Jackson (Largest city: Seymour) • Jay (Largest city: Portland) • Jennings (Largest city: North Vernon) • Johnson (Largest city: Greenwood) • LaGrange (Largest city: LaGrange) • Lawrence (Largest city: Bedford) • Marshall (Largest city: Plymouth) • Martin (Largest city: Loogootee) • Miami (Largest city: Peru) • Montgomery (Largest city: Crawfordsville) • Morgan (Largest city: Martinsville) • Newton (Largest city: Kentland) • Noble (Largest city: Kendallville) • Ohio (Largest city: Rising Sun) • Orange (Largest city: Paoli) • Owen (Largest city: Spencer) • Parke (Largest city: Rockville) • Pulaski (Largest city: Winamac) • Putnam (Largest city: Greencastle) • Randolph (Largest city: Winchester) • Ripley (Largest city: Batesville) • Rush (Largest city: Rushville) • St. Joseph (Largest city: South Bend) • Shelby (Largest city: Shelbyville) • Steuben (Largest city: Angola) • Tipton (Largest city: Tipton) • Union (Largest city: Liberty) • Wabash (Largest city: Wabash) • Warren (Largest city: Williamsport) • Washington (Largest city: Salem) • Wayne (Largest city: Richmond) • Wells (Largest city: Bluffton) • White (Largest city: Monticello) • Whitley (Largest city: Columbia City)