Incumbent Democratic Senator Patty Murray won re-election to a fourth term by a margin of 52.4% – 47.6% over Republican Dino Rossi, who had run for governor in 2004 and 2008.

This was the last U.S. Senate election in Washington where the margin of victory was single digits.

The top 2 candidates from the blanket primary advanced to the general election.

In response, Murray said, "You bet that seniority and leadership has a big thing to do with it, but the other part of it is, I get up every day and I work hard and I believe in this and I am going to continue fighting for the community I represent.

"[17] The National Rifle Association spent $414,100 supporting Rossi and opposing Murray in the 2010 senatorial contest.