Each harped on his background, trying to prove that he was the more conservative candidate: Romney played up his work in private businesses, while Gingrich spoke of his fondness for the principles of Ronald Reagan.
"I've worked in the private sector," Romney said.
To which Gingrich countered, "I helped Governor Reagan become President Reagan."
There were two other candidates at the debate -- Rick Santorum and Ron Paul -- but neither got much time in the spotlight.
Paul told the debate's moderator, NBC's Brian Williams, that he has "no plans" to run for president as a third-party candidate if he doesn't win the Republican nomination.
"I have no intention," Paul said. "I don't want to."
Santorum, meanwhile, continued to try to portray Romney and Gingrich as too moderate by tying them to the policies in President Obama's health care program.
"Governor Romney's plan in Massachusetts was the basis for 'ObamaCare,'" he said. "Speaker Gingrich, for 20 years, supported a federal individual mandate."
The debate included a number of questions pertinent to Florida, like space exploration and the years-old case of Terri Schiavo.
Paul, a doctor, was asked about his view of the debate over Schiavo -- a woman in a persistent vegetative state whose husband and family fought over whether to let her die -- and said it was a reminder for everyone to "have a living will" so families can make a decision.
"This was way out of proportion to what happens more routinely," he said. "But it should urge us all to try to plan for this."
On funding NASA, Gingrich discouraged "building a bigger bureaucracy" but said that private-sector investments and incentives for space exploration work would get Florida's economy going. He also talked of "romantic and exciting futures."
The candidates spent a significant portion of the debate exchanging views on Iran, but also on another foreign policy issue that is a prime topic in Florida: immigration.
Questioned on his plan to encourage illegal immigrants to return to their countries to reapply for citizenship, Romney said his proposal for "self-deportation" would provide a "transition period" for undocumented workers who would have to decide at the end of that time whether they want to stay without valid papers or leave.
On a similar topic, the candidates debated having English as the country's official language. Paul said that while he, like all of the candidates, support that, he wouldn't support a federal effort to ban initiatives like ballots in Spanish.
"You can solve some of these systems without dictating one answer for all states," Paul said.
Romney and Gingrich took more hard-line stances.
"People need to learn English to be able to be successful," Romney said.
"It is essential to have a central language," Gingrich said.