Bill Janklow Republican Stephanie Herseth Democratic Measure 9 Amendment A Amendment E Amendment G The 2004 South Dakota's at-large congressional district special election, which was held on June 1, 2004, was triggered by the January 20, 2004 resignation of Republican Representative Bill Janklow following a conviction of vehicular manslaughter after an accident that had occurred in August 2003.

Republicans nominated Larry Diedrich over Barbara Everist, also a South Dakota State Senator.

The Hill committees of both parties spent a combined total of two million dollars on advertising in South Dakota.

Vice President Dick Cheney came to South Dakota in March to campaign for Diedrich.

The both of them won the regular primaries held on the same day as the special election, with Herseth winning a full term in November 2004 in a rematch with Diedrich.