Mike Pompeo Republican Ron Estes Republican A special election was held on April 11, 2017, to determine the member of the United States House of Representatives for Kansas's 4th congressional district after the incumbent, Mike Pompeo, resigned because of his nomination by President Donald Trump as Director of the Central Intelligence Agency.

[9][10] Republican Donald Trump won the district by a 27-point margin in the 2016 presidential election, receiving 60% of the vote to Democrat Hillary Clinton's 33%.

[11] On January 23, 2017, the U.S. representative for Kansas's 4th congressional district, Mike Pompeo, resigned after being nominated by President Donald Trump as Director of the Central Intelligence Agency.

[14] Although not initially expecting a close race, the National Republican Congressional Committee (NRCC) spent $100,000 on advertising in the last week of the campaign, and Republican politicians Sen. Ted Cruz of Texas, President Donald Trump, and Vice President Mike Pence recorded robocalls or campaigned in person supporting their nominee Ron Estes.

This not only marked a dramatic shift from the 61.6%–29.6% margin that Pompeo had been re-elected by in the previous year's regularly-scheduled election, but this was also the closest race in the district since incumbent Todd Tiahrt, who held the seat from 1995 to 2011, edged out Democrat Randy Rathburn by 3% in 1996.