Nineteen species of fleas are presently known from Florida. Pulex simulans, Corrodopsylla hamiltoni, and Orchopeas leucopus are here recorded from the state for the first time. Considering only wild mammals, the number of flea species found on a particular host ranged from 1 to 6, whereas the number of hosts infested by a given species of flea varied from 1 to 13. Six of the fleas recorded from the state are introduced or cosmopolitan, 4 have Neotropical affinities, and the remainder have Holarctic or Nearctic affinities. One of the latter group has apparently been introduced from western United States. The present data suggest that most of the northern fleas occurring in Florida reach the limits of their range in the northern part of the State and are uncommon. Still other northern species that extend well into southeastern United States apparently fail to reach Florida. As suitable hosts occur beyond the known range of all of these fleas, the southward limitation of their ranges appears to be attributable to climatic factors.