In this study, 173 stomach contents of prussian carp were examined and they have been caught during period of January, 2000- September, 2003 from Bafra Fish Lakes via a number of alternative nets and tackles. Organisms, obtained after analysing the digestive system contents the prussian carp patterns, were examined using method of Geometric Index of Importances (GII). Some of the plant food items which are dominant in the stomach contetns of prussian Carp are Navicula, Amphora and Cymbella. Animal food items are Daphnia, Bosmina and Copepda members. Consequently, 47 food items (38 organisms were plants and 9 were animals) were found in the digestive system contents of the Prussian carp. As a result of Geometric Index of Importance, prussian carp is omnivorous.