Clinton promptly declared it a welcome victory. 's camp dismissed it as meaningless.
The New York senator, fresh off her lopsided loss to Obama in last weekend's South Carolina primary, arranged a rally in the state as the polls were closing, an evident attempt to gain campaign momentum.
She and Obama collide next week in a coast-to-coast competition for delegates across 22 states.
"I am convinced that with this resounding vote, with the millions of Americans who will vote next Tuesday, we will send a clear message that America is back and we will take charge of our destiny once again," she said to a boisterous crowd.
Last year, the national party stripped Florida of its delegates as punishment for moving its primary ahead of Feb. 5 and the candidates pledged to bypass the state. At stake Tuesday were 185 delegates.
Still, Clinton winked at that pledge, holding two closed fundraisers in recent days and scheduling a rally with supporters after the polls closed in Florida.
It is expected that the eventual nominee will try to seat delegates from Florida and Michigan, reversing the Democratic National Committee's punishment.
"I could not come here in person to ask you for your votes, but I am here to thank you for your votes today," she said. "This has been a record turnout because Floridians wanted their voices to be heard. I promise you I will do everything I can to make sure not only are Florida's Democratic delegates seated but Florida is in the winning column for the Democrats in 2008."
Clinton's chief strategist, Mark Penn, citing the turnout of 1.5 million Democrats, called the results "significant" and "far more than symbolic."
But the Obama camp said that without delegates, the outcome yielded nothing.
"Now that Senator Clinton has lost badly in South Carolina, she's trying to assign meaning to a contest that awards zero delegates and where no campaigning has occurred," Obama spokesman Bill Burton said.
Clinton rejected the criticism as "typical campaign jargon" and invoked the memory of the disputed 2000 general election results in Florida.
"The way we're going to get to have the next president be a Democrat is to make sure that every state believes that its votes count," she said in an interview on MSNBC. "And there isn't any state where that's more important than Florida because of recent history."
Michigan also violated party rules by moving its primary to Jan. 15, and party leaders voted to strip the state of its 156 delegates as punishment. Clinton has also made a plea for Michigan delegates to be seated at the convention.
Democrats participated in Tuesday's primary, driven to vote in part by ballot initiatives on property tax relief and gambling in some counties.
Exit polls of Florida Democrats conducted for The Associated Press and the television networks showed that the economy was the most important issue facing the country. Half of Democrats called the economy poor, compared to only about one in seven Republican primary voters.
Both parties' electorates were older than in any other presidential contest this year. A third or more in each primary were at least 65 years old. In earlier Democratic contests no more than a quarter were senior citizens.