Seasonal variation in the species composition of the benthic algae of Karagol Lake was investigated from April to October in 2001 ard 2002. The benthic algal flora consisted of 38 taxa belonging to the divisions Chlorophyta. Cyanophyta, Euglenophyta, and Chrysophyta. In general, Chlorophyta were dominant in terms of species number and abundance during the study period. The distribution range of the benthic algae composition and dominant species differed from each other at all stations. Benthic algal growth was mostly influenced by water temperature and light.