Between April and November 1997, a total of 208 specimens of Garra rufa (Heckel, 1843) were caught from the Asi River and its tributaries. It was observed that 68.3% of the guts were empty. The ratio of emptiness of the guts at age 3 and older was low when compared to younger specimens. Garra rufa grazes on aquatic plants and mainly feeds on plant materials that mostly consist of benthic chrysophytes and phytoplankton, except for a few rotifers and protozoa. Two specimens were infected by parasitic nematodes. Navicula sp., Gomphonema sp. and Nitzschia sp. were abundant as 34.2%, 17.3% and 12.0% and frequent as 66.7%, 63.6% and 42.4%, respectively, in the samples and Cymbella sp., Cyclotella sp., Scenedesmus sp., Rhoicosphaenia sp., Cocconeis sp. and Oscillatoria sp. were also very frequent food organisms in the gut contents of samples. The distribution of food organisms in the gut content appeared to depend on the location (higher occurrence and abundance of the different food items in downstream locations). However, it was concluded that season was the most important factor influencing G. rufa diet.