One hundred and thirty-five specimens of Acipenser stellatus were collected from the fishery stations of Babolsar, Farahabad and Bandar-e-Torkaman, south-eastern Caspian Sea between the winter of 2001 and spring 2003. The content of the alimentary canal was studied fresh, prey items were separated and then fixed in 10% formalin for identification. The probability percentage and frequency of various prey items, the percentage of empty stomachs along with prey dominance were calculated. Nine of the registered food items were considered to be the principle and dominant food items and had very high importance as demonstrated by the dominance index. The percentage of alimentary canal emptiness in spring was lower than that in other seasons. Seasonal changes in food composition were observed. ANOVA analysis showed no significant difference of prey preference among sampling sites while we found significant differences among seasons.
