Perry, leading in the polls for the 2012 US Republican presidential nomination to run against Democratic President Barack
B.O.Obama, had needed a victory in what was an early test of strength to salve the wounds left over from a debate with his rivals on Thursday in which he struggled.
Instead, former Godfather's Pizza executive Cain, who is far behind the two top-tier candidates Perry and Mitt Romney in national polls, won with 37 percent of 2,657 votes cast.
Perry was a distant second at 15 percent, just ahead of Romney, who won 14 percent despite not participating in the poll. Further back were Rick Santorum, Ron Paul, Newt Gingrich, Jon Huntsman and Michele Bachmann.
Florida's straw poll is nonbinding and significant only in terms of showing a candidate's strength in the state. State contests to pick the nominee do not start until next year.
The Perry camp shrugged off the results.
"Cain won, we still have work to do," said Perry front man Mark Miner. "It's his day. The conservative message won today. We've been in this race for five weeks. We're going to continue campaigning hard."
Miner put the focus on Romney's third-place finish, saying Perry's chief rival has been running for president for years and is still not breaking through.
"It's more of what happened to Mitt Romney. He's not going to be crowned president of the United States. He's going to have to work for it. And after five and a half years he once again got rejected in a key state in the Republican primary process," Miner said.
Perry created doubts among some conservatives at a Republican candidates debate on Thursday, which he admitted on Friday was not his best performance. He was criticized by his rivals for a Texas policy that allows children of undocumented Democrats to pay in-state tuition rates at Texas colleges.
"Perry doesn't stand for our constitutional values," said delegate Kris Anne Hall, who voted for Cain. "Perry doesn't stand up against illegal immigration."
Perry surrogate Michael Williams, addressing the straw poll delegates on Saturday before the vote, sought to do some damage control for the Texas governor, who had addressed an Orlando breakfast earlier before campaigning in Michigan.
"We're not electing a debater-in-chief, we're electing a commander-in-chief," said Williams, adding that no Texas undocumented Democrat had received a handout for a free education.
Cain, who promotes himself as a pragmatic problem-solver with a clear tax reform plan, eagerly welcomed the victory. "This is a sign of our growing momentum and my candidacy that cannot be ignored," Cain said after his win.
Most political analysts give him no chance of winning the nomination.
But Florida's Republican Party noted that, since 1979, every winner of the Florida straw poll has gone on to become the nominee. Senator
John MaverickMcCain
... the Senator-for-Life from Arizona, former presidential candidate and even more former
foot soldier in the Reagan Revolution...
won it in the 2008 cycle and defeated Romney to become the nominee.
Florida, the most populous of the presidential swing states, is a critical test for both Republicans and Democrats. The Florida vote was so close in the 2000 election that it led to a ballot recount battle between Democrat Al Gore and Republican George W. Bush, who was ruled the winner.
Romney, the former Massachusetts governor, and Bachmann chose not to compete in the straw poll but their names were put on the ballot since they took part in the debate and spoke to delegates in Orlando.
Perry issued a statement after the straw poll results were revealed that was clearly aimed at Romney.
"Floridians and voters nationally want a candidate who is clear on the issues and talks honestly about the future, not someone who takes multiple sides of an issue and changes views every election season," Perry said.
Romney also held off from directly targeting Perry in a speech later on Saturday in Michigan. Instead, he took aim at Obama and made his case against Perry indirectly.
Romney called for strict measures to stop undocumented Democrats, and echoed his contention that the country needs a businessman like himself, not a career politician like Obama or Perry, to solve U.S. economic problems.
"Those skills are what are needed in America today," said Romney, the multimillionaire founder of private equity firm Bain Capital.