Benthic macroinvertebrate fauna of Istranca stream were investigated in 18 stations which belong to Istranca Stream by six times sampling from September 2011 to August 2012. 6066 individuals belonging to Bivalvia (5 taxa), Gastropoda (11 taxa), Malacostraca (1 taxon), Ephemeroptera (17 taxa), Odonata (11 taxa), Plecoptera (6 taxa), Hemiptera (9 taxa), Coleoptera (15 taxa), Megaloptera (2 taxa), Trichoptera (7 taxa) and Diptera (15 taxa) were determined. Dominancy (%) of Taxa according to specimen number were calculated. In terms of water quality, Criteria of Regulation on the Management of Surface Water Quality (2016) indicate that water quality constitutes to the Pt and 2nd water quality. The study is the first and detailed study is to determine benthic macroinvertebrate fauna on Istranca Stream.