The seasonal variations of species belonging to the family Chironomidae along with some physical and chemical properties of Kesikköprü (Ankara) dam lake during the period of April 1995- May 1996 were investigated. Chironomid larvae were composed of 26 % of benthic fauna. Ten species of Chironomids were recorded from dam lake. Also, temperature of lake water and weather, pH, oxygen, light permeability and depth were measured monthly. Results showed that the Kesikköprü dam lake is olygotrophic.
