Blunt made the announcement in a video posted on YouTube.
Blunt said in a video that "after 14 general election victories — three to county office, seven to the United States House of Representatives, and four statewide elections — I won’t be a candidate for reelection to the United States Senate next year."
The 71-year old Blunt, a member of Senate GOP leadership, said that he will finish out his current term, which runs through the end of next year.
He becomes the fifth Republican senator to retire rather than run for re-election in 2022, as the GOP tries won win back the Senate majority it just lost in the 2020 election cycle.
Sens. Pat Toomey of Pennsylvania, Rob Portman of Ohio, and Richard Shelby of Alabama have all announced the past couple of months that they would not launch re-election campaigns. Sen. Richard Burr of North Carolina said during his 2016 re-election that he wouldn’t run again in 2022.
Two other Senate Republicans are also mulling retirements: 87-year old Sen. Chuck Grassley of Iowa and Ron Johnson of Wisconsin.
The Senate is split 50-50 between the two parties, but the Democrats hold a razor thin majority, due to the tie-breaking vote of Vice President Kamala Harris, who serves as president of the Senate. That means the GOP only needs a one seat pickup to regain the majority. But Republicans are defending 20 of the 34 seats up for grabs in 2022.
Blunt, who was first elected to the Senate in 2010 after serving as GOP whip during his 14 years in the House, said in his video that "in every job Missourians have allowed me to have, I've tried to do my best. In almost 12,000 votes in the Congress, I'm sure I wasn't right every time, but you really make that decision based on the information you have at the time."
Missouri was once a competitive state, but has trended Republican in recent decades.
President Bill Clinton in 1996 was the last Democrat to win the state in the race for the White House, and then-Sen. Claire McCaskill’s 2012 victory was the last time a Democrat won a Senate election in the state.
McCaskill, who lost her 2018 re-election bid, to Republican challenger Josh Hawley, took to Twitter to write "To all that are asking: thank you to the many who have said kind things. But I will never run for office again. Nope. Not gonna happen. Never. I am so happy I feel guilty sometimes."
Sen. Rick Scott of Florida, chair of the National Republican Senatorial Committee, which is the Senate GOP's re-election arm, said in a statement that "the NRSC will work tirelessly to ensure Senator Blunt’s successor will uphold his legacy of free enterprise and small government and we will hold this seat."
Democratic Senatorial Campaign Committee executive director Christie Roberts charged that "Senate Republicans have a retirement problem."
And the pro-Democrat outside group American Bridge argued that Blunt's retirement announcement "is yet another sign that Republicans are running scared from a resurging Democratic Party with the winds at our backs."