A 1-year study on the occurrence of ectoparasites on farmed and wild common carp (Cyprinus carpio L., 1758) and their relationship with temperature and culture conditions was conducted between June 1994 and May 1995 at two sites in the Sinop region of northern Turkey. Following the investigation of 125 common carp, Trichodina acuta Lom, 1961, Trichodina mutabilis Kazubski and Migala, 1968, Trichodina nigra Lom, 1960, Trichodinella subtilis Lom, 1959, Apiosoma piscicola Blanchard, 1885, Epistylis sp., Dactylogyrus anchoratus Dujardin, 1845, Dactylogyrus extensus Mueller and Van Cleave, 1932, Gyrodactylus sp. and Argulus foliaceus L., 1758 were identified. Trichodina mutabilis and Dactylogyrus extensus were found to be the most common ectoparasites on both the farmed and the wild common carp. The overall infestation prevalence was 100% on farmed carp and 93.6% on wild carp. Dactylogyrus anchoratus represents a new parasite record for Turkey. © 1999 Taylor & Francis Group, LLC.