2018Final results
2018 election for U.S. Senate in Montana
U.S. Senate · Montana
Jon Tester (D) won with 50.3% of the vote, defeating Matthew M. Rosendale, Sr. (R) by 3.6 points.
Jon TesterDemocrat · winner
50.3%253,876
Matthew M. Rosendale, Sr.Republican
46.8%235,963
Rick BreckenridgeLibertarian
2.9%14,545
504,384 votes
Source: MIT Election Data and Science LabUpdated Oct 1, 2026, 6:17 AM ET
The seat over time
D − R margin in this seat's races around 2018
Races before and after
Source: MIT Election Data and Science LabUpdated Oct 1, 2026, 6:17 AM ET
Money in this race
Each line compares the two campaigns on one scale.
Jon TesterMatthew M. Rosendale, Sr.
$18.7M
Raised by the campaign
$6M
$19.8M
Spent by the campaign
$5.9M
$480.6K
Cash on hand
$76.2K
Campaign money: FEC, through Dec 31, 2018.
Source: FEC campaign filingsUpdated Dec 31, 2018
The candidates
Jon Tester (D)Matthew M. Rosendale, Sr. (R)
Also on the ballot: Rick Breckenridge (Libertarian), 2.9%