Also, Texas Gov. Rick Perry shook up the campaign by announcing he's running.
In the Iowa straw poll, Bachmann got more than 28 percent, Congressman Ron Paul picked up more than 27 percent and former Minnesota Gov. Tim Pawlenty came in third with more than 13 percent. The other candidates were in single digits or less.
In the past, winning the straw poll has not necessarily translated into victory at the Iowa caucuses. But political observers say it has helped whittle down the field.
At a fundraiser in southwest suburban Lemont on Saturday night, guests who paid $2,000 a couple to meet House Speaker John Boehner reflected on Bachmann's win.
"I think she's a good candidate, has a lot of supporters, and I'm excited to see how everything turns out in the races," said Green Oaks resident Megan Wales.
Bachmann, the first ever female straw poll winner, once lived in Iowa.
"You have just sent a message that Barack Obama will be a one-term president," Bachmann said.
Another Minnesotan, Pawlenty, finished a distant third despite months of heavy campaigning in Iowa. Though the Pawlenty camp called it a strong showing, political observers say his future prospects look dim.
"He has very limited resources. He has very limited dollars. And if he doesn't get a jump out of this thing, he's not going to be able to raise the money," said Matthew Dowd, ABC News Political Analyst.
While Texas Congressman Ron Paul came in a close second in the straw poll, it was another Texan, Perry, who stole some of Iowa's thunder Saturday by announcing in South Carolina that he's running for president.
"I promise you this: I will work every day to try to make Washington DC as inconsequential in your life as I can," Perry said.
Perry is the Lone Star State's longest serving governor. He's a no tax, cut regulation, small government conservative who can boast about job growth, but Democrats in his state are critical.
"People would be praying for our country to survive someone whose primary emphasis will be on right-wing ideological zealotry," said Rep. Lloyd Dogget, D-Texas.
Perry could pose a threat to early front-runner Mitt Romney, who largely sat out the Iowa straw poll.
Also absent on Saturday's ballot was former Alaska Gov. Sarah Palin, who has yet to announce a run, but it didn't keep her from visiting Iowa.
"I'd eliminate the uncertainty in the economy and let our job creators know, number one, we will cut taxes," Palin said.
On Saturday night, Bachmann is using her victory as a fundraising tool. Perry is also making a push for campaign cash, and his team hopes to raise up to $10 million in the next few weeks.
Congresswoman Michele Bachmann - 4823 votes, 28.55 percent
Congressman Ron Paul - 4671 votes, 27.65 percent
Governor Tim Pawlenty - 2293 votes, 13.57 percent
Senator Rick Santorum - 1657 votes, 9.81 percent
Herman Cain - 1456 votes, 8.62 percent
Governor Rick Perry - 718 votes, 3.62 percent (write-in)
Governor Mitt Romney - 567 votes, 3.36 percent
Speaker Newt Gingrich - 385 votes, 2.28 percent
Governor Jon Huntsman, 69 votes, 0.41 percent
Congressman Thad McCotter = 35 votes, 0.21 percent
About 162 votes, or 0.96 percent, includes all those receiving votes at less than one-percent that were not on the ballot.