The parasites of indigenous populations of mourning doves (Zenaida macroura) in north and south Florida were compared with those of an introduced population of white-winged doves (Z. asiatica) in south Florida. Thirty-two species of parasites including 5 protozoans, 7 nematodes, 2 trematodes, 2 cestodes, 7 acarines, 7 mallophagans, and 2 dipterans were found. Of these, 16 were common to both species of doves. Mourning doves from north Florida showed a more diverse parasite fauna than did the white-winged or mourning dove populations from south Florida. Nematodes were the most common parasites in all three populations; infected doves contained one or two nematode species per dove. Total helminth burdens per infected dove averaged 13.1 for white-winged doves, 19.9 for mourning doves in south Florida, and 6.6 for mourning doves in north Florida. The prevalence of infections by Trichomonas gallinae was higher in white-winged doves (97%) than in mourning doves in south Florida (17%) or in mourning doves in north Florida (1%). The high prevalence of this parasite in expanding populations of white-winged doves may pose a threat to mourning dove populations since some strains of T. gallinae are pathogenic.