Seasonal changes of proportional distribution, biotic indices, abundance, and frequency of benthic macroinvertebrate communities in Menderes Creek were investigated at 5 stations between November 2005 and July 2006. The fauna included a total of 87 taxa belonging principally to Insecta (52 taxa, especially Chironomidae), Oligochaeta (12 taxa), Mollusca (11 taxa), Hirudinae (7 taxa), and Malacostraca (5 taxa). Mean density was estimated to be 778 individuals m(-2) for the 87 taxa. Mollusca (38.5%) and Insecta (39.9%) are the dominant groups among the macroinvertebrate assemblages. Average Shannon-Wiener diversity index was calculated as 1.41, average Margalef's richness index was 1.27, and average Pielou index was 0.61. The results of one-way analysis of similarity (ANOSIM) indicated that macroinvertebrate compositions were significantly different between sampling sites (p<0.05). ANOSIM and similarity percentage analysis (SIMPER) revealed significant differences and a high degree of community dissimilarity within and between the sampling stations.