A study of the diplozoid species Paradiplozoon homoion on the gills of Pseudophoxinus antalyae was conducted. A total of 240 P. antalyae were examined from December 2005 through to June 2006 with monthly intervals for seasonal occurrence and site selection of P. homoion. Of the 240 fish examined, 131 (54.6 %) were infected with P. homoion. A total of 705 parasites were recorded, the maximum intensity of infection was 32 specimens of P. homoion in February on a single fish. The prevalence of the parasite varied with fish body size. The highest frequency of occurrence was found on fish in the 12-17.9 cm size classes. Branchial distribution of P. homoion was studied in monospecific infections. There were no preference found in the distribution of P. homoion over the gill arches between left and right sides of the host (P<0.05). There were also no significant differences in the number of P. homoion between the gill arches (P=0.05), but gill arches II and III were preferably infected (30.9% and 27.8% respectively) when compared with the gill arches I and IV.