Sen. Dean Heller (R) was able to overcome President Barack Obama's Nevada coattails and defeat Rep. Shelley Berkley (D).
The Associated Press called the race around 4 a.m., with Heller leading by about 1 point.
The Silver State race is one of the few disappointments for Democrats on the Senate map this year. It was expected that Obama would have to carry the state by a large margin for Berkley to win. He won by more than 6 points, but it was not enough for Berkley.
Heller, who was appointed to the Senate last year, was thought to be especially vulnerable because he voted for Rep. Paul Ryan's controversial budget blueprint as both a Member of the House and Senate.