In this study, examinations were conducted on Argulus foliaceus (Crustacea, Branchiura) infes-tation in 114 individuals of Leuciscus cephalus supplied from Serban Dam Lake between the dates of February 2009 and August 2010. Argulus foliaceus (.5, 6.1±5.1) was found on gills, fins and skin of the host fish specimens. A. foliaceus was recorded on smaller host fish size specimens than bigger ones in summer time, during the study period. In addition, the prev-alence of the parasite was recorded higher on male sex group than female. However, mean in-tensity of parasite was found higher on female than male fish specimens.