This study is concerned with the feeding behavior of pikeperch (Sander lucioperca (L., 1758)) living in Hirfanli Dam Lake constructed on the Kizilirmak River. There were 326 pikeperch caught between August 1996 and July 1997. The fork length and weight of the pikeperch caught ranged between 105 and 529 mm and 12 and 1520 g in the general population. Pikeperch are carnivorous and piscivorous and they eat their own species when nutrients are lacking. The smallest fish-swallowing length was determined to be 145 mm. A cannibalism rate of 40.5% among pikeperch of 145-378 mm in length living in the lake was observed. The stomach content of individual pikeperch was as follows: Gammarus (27.7%), Diptera larvae and pupae (22.7%), fish and fish remains (22.1%), Odonata nymphs (9.8%), organism remains (9.5%), Mysis (6.0%), Isopoda (1.9%) and fibrous algae (0.3%).