This study was carried out between March 2011 and February 2012 on Degirmendere Stream in order to determine the water quality of the stream, and to investigate the environmental quality and the applicability of both the Biological Monitoring Working Party (BMWP; Original, Spanish, Hungarian, Czech, and Polish versions) and Average Score Per Taxon (ASPT; Original, Hungarian, and Czech versions) indices. The biotic and diversity indices were applied using the ASTERICS software program. As a result, a total of 59 taxa were detected: 4 taxa from Gastropoda, 1 taxon from Bivalvia, 1 taxon from Oligochaeta, 1 taxon from Hirudinea, 2 taxa from Crustacea, and 50 taxa from Insecta. The water quality of Degirmendere Stream was found to be unpolluted/slightly polluted according to the physicochemical data and the different versions of the BMWP and ASPT. However, the score values of the different versions of the BMWP were different from each other because the versions of the BMWP were adapted based on the geological and ecological features of their source countries. The results of this study suggest that there is still a need for much intensive investigation and further testing of the effectiveness of the BMWP and ASPT indices for use in the streams of Turkey. The findings also strongly indicate that these indices should be adapted based on the geomorphological and environmental features of Turkey.