The poll conducted by Mason-Dixon Polling & Research for the Tampa Tribune and WFLA-TV gave Bush 48 percent vs. 46 percent for Kerry and showed third-party candidate Ralph Nader with 2 percent, with 4 percent undecided.
"The state is getting as close as everyone expected it to be," said David Niven, professor of political science at Florida Atlantic University.
The 2-point match falls within the polls margin of error of 4 percentage points, but shows significant gains for Kerry.
A Mason-Dixon poll in April showed Bush with a 51 percent to 43 percent lead over the challenger.
Ten percent of the independents who were surveyed said they remain undecided, but 44 percent favored Kerry to 38 percent for Bush and 8 percent for Nader.
"We're looking at a close race. You really have a sharp, sharp split among voters," Mason-Dixon pollster Brad Coker said.
He also said the independent vote "is something for Bush to be concerned about."