In order to determine the relationships between aquatic Oligochaeta and larval Chironomidae assemblages (species and individual numbers) and environmental variables, sampling was made at 9 different stations of Kovada Channel and its linked lakes (Lake Egirdir and Lake Kovada) at monthly intervals during 1 year, between July 2010 and June 2011. Canonical correspondence analysis (CCA) was used to characterize the relationships between Oligochaeta-Chironomidae fauna and the environmental variables. As a result, 23 taxa belonging to Oligochaeta and 20 taxa to Chironomidae were determined. Also, it was found that the main environmental parameters influencing composition of organisms were NO3-N, Sigma P, BOD, and DO. Stations were clustered using the unweighted pair-group method with arithmetic mean (UPGMA) based on organisms of Oligochaeta and Chironomidae. Stations 7 and 9 were found to be most similar to each other. According to Shannon-Weaver and Simpson diversity indices, station 5 (located at Kovada Channel) was found to have the highest diversity while station 1 (located at Lake Egirdir) had the lowest one.