In this study, metazoan parasites of the common carp (Cyprinus carpio L. 1758) in Dalyan Lagoon were observed from September 1997 to December 1998. During this study, a total of 43 common carp were caught and metazoon parasites were investigated. A total of 3 species of metazoon parasites were found on 31 of the 43 fish examined. The following parasites were found: Dactylogyrus extensus (Monogenea) and Ergasilus sieboldi (Crustacea) on the gills of host fish and Caryophyllaeus laticeps (Cestoda) in the intestine of host fish. One of these species, D. extensus, occurred throughout all months in the study period and was the dominant parasite species found in common carp. In the 31 fish infected by D. extensus a total of 704 parasites were found. Ergasilus sieboldi was the second most dominant parasite in this study. Caryophyllaeus laticeps was found in 1 of the 43 fish examined. It contained one parasite.