This study examines temporal changes and predator size-dependent changes in the important dietary groups and feeding intensity of pikeperch Sander lucioperca. Monthly experimental fishing operations were conducted for sampling purposes using gillnets with different mesh sizes between July 2009 and June 2010. The results showed significant changes in the important dietary items as a function of predator size. Diptera and mysids were the most important groups for pikeperch smaller than 19 cm, whereas fish were most important for pikeperch larger than 19 cm. The important dietary items also varied significantly over time. The most important dietary groups were mysids during December, January and February; diptera during March and April; and teleosts during the other months. The feeding intensity of pikeperch peaks in October and March and then progressively decreases between October and February. The decrease in feeding intensity was related to the reproductive period.