The four candidates vying to replace Radel are Florida state Sen. Lizbeth Benacquisto, former CEO Curt Clawson, aerospace and defense consultant Michael Dreikorn and physician Paige Kreegel.
The AP reported earlier on the state of the race:
The campaign in the solidly GOP district to replace Trey Radel has been marred by allegations of connections to child sex offenders, questionable business dealings and negative attack ads.
The winner of Tuesday's special election will still likely defeat a Democratic challenger in the June 24 general election.
In a covert operation in October 2013, an undercover police officer sold Radel 3.5 grams of cocaine for $250 at a Washington, D.C. restaurant. He later pleaded guilty to cocaine possession and was sentenced to one-year probation.