Bachmann announced her decision in a video on her website.
"My decision was not influenced by any concerns about my being re-elected," Bachmann said. She narrowly won a fourth term in 2012 over Democrat Jim Graves, a hotel chain founder who is running again in 2014.
Bachmann also said, "This decision was not impacted in any way by the recent inquiries into the activities of my former presidential campaign." In January, a former Bachmann aide filed a complaint with the Federal Election Commission, claiming the candidate made improper payments to an Iowa state senator who was the state chairman of her 2012 presidential run. The aide, Peter Waldron, also accused Bachmann of other FEC violations.
Bachmann had given few clues she was considering leaving Congress. Her fundraising operation was churning out the regular pitches for the small-dollar donations that Bachmann corralled so well over the years, and she had an ad running on Twin Cities television talking about her role in opposing President Barack Obama's health law.
Without the polarizing Bachmann on the ticket, Republicans could have an easier time holding a district that leans more heavily in the GOP direction than any other in Minnesota.
Graves said he thought Bachmann had "read the tea leaves."
"The district is changing," the Democrat said in an interview Wednesday with KARE-TV in Minneapolis. "They want somebody who really does have some business background and understands the economy and can get things done in Washington and back in the district."
Andy Aplikowski, who has long been active in the district's Republican Party chapter, said he expected Bachmann to run again but can understand why she didn't.
"It's a grueling thing to be in Congress. It's a grueling thing to be Michele Bachmann in Congress," he said. "Every move you make is criticized and put under a microscope."
Bachmann won the seat in 2006 on the strength of a social and fiscal conservative coalition. She catapulted onto the national scene with edgy comments and frequent cable television appearances, including one where she suggested then-candidate Obama may have harbored "anti-American views." Her profile shot up even more with the rise of the tea party, whose agenda she heartily championed in Congress much before other Republicans saw the movement's political potential. She tried to harness the tea party energy with her presidential campaign in 2012.
The White House bid got off to a promising start, with a win in an Iowa GOP test vote. But Bachmann quickly faded and finished last when the real voting started in Iowa's leadoff caucuses, a result that caused her to drop out. Saddled with debt, Bachmann opted to campaign again for her seat and squeaked through.
But the failed presidential campaign continued to dog her. Allegations of improper payments prompted ethics inquiries. Bachmann also faced a lawsuit from a former aide that alleged someone on the congresswoman's team stole a private e-mail list of home-school supporters for use in the campaign. That case is pending.
Bachmann, a vocal opponent of the Obama administration, promised her supporters, "I will continue to work overtime for the next 18 months in Congress defending the same Constitutional Conservative values we have worked so hard on together."
As for her plans beyond Congress, she said, "There is no future option or opportunity, be it directly in the political arena or otherwise, that I won't be giving serious consideration if it can help save and protect our great nation."
Bachmann has been mentioned as a potential challenger to first-term Democratic Sen. Al Franken, but she has given little indication that she would take that step.
A spokesman said Bachmann would not be available for interviews Wednesday.
Kesten reported from Washington.