In the first 2008 presidential nominating exercise in the nation, Obama, the freshman senator from Illinois, oout-polled Sen. Hillary Clinton, D-N.Y., and former North Carolina Sen. John Edwards, winning 38 percent support among caucus goers.
"You have done what the state of New Hampshire can do in five days," Obama told supporters as he claimed victory. "You have done what America can do this year, in 2008. Our time for change has come."
Edwards and Clinton spoke of change as they congratulated Obama.
Edwards said the Iowa outcome showed that "the status quo lost and change won."
"Today we're sending a clear message that we are going to have change," said Clinton, "and that change will be a Democratic president in the White House in 2009."
Huckabee, the former Arkansas governor, had the support of 34 percent of Republican caucus goers with 86 percent of precincts reporting.
Huckabee, an ordained Southern Baptist minister, beat former Massachusetts Gov. Mitt Romney despite being dramatically outspent by Romney, a wealthy venture capitalist.
"People really are more important than the purse," said Huckabee in claiming victory, "and what a great lesson for America to learn."
"You win the silver in one event it doesn't mean you're not going to come back and win the gold in another event, and that we are going to do," said Romney, alluding to his experience running the Winter Olympics in Salt Lake City.
Despite the cold weather, Iowa caucus goers came out in strong numbers at nearly 1,800 precincts, CNN reported.