In this study, water and epilithic diatom samples were collected from 6 stations selected between July 2010- June 2011 along the Andik Stream. The most dominant genus in station 1 was Navicula (36,42%), in station 2 Navicula (26,86%), in station 3 Ulnaria (24,98%), in station 4 Navicula (32,6%), in station 5 Cocconeis (15,41%), in station 6 Nitzschia (55,51%) at the Andik Stream. At the first three stations and station 5, the most dominant species was Ulnaria ulna (in station 1 26,21%, station 2 25,93%, station 3 24,98%, station 5 13,73%), in station 4 Achnanthes minitussima Brebisson (22,87%) and in station 6 Nitzschia palea (Ktitzing) W.Smith (48,63%). According to Physicochemical parameters, the first five stations were determined as oligosaprop and station six as betamesosaprob. Also, the water quality of Andik stream was determined according to diatom taxa by using OMNIDIA Software Program. Results show that the indices have quite low correlation with the chemical variables and that GDI seems to be the best while DAP seems to be the worst for our study. Besides, the pollution in station 6 has increased according to all indices applied. Although GDI yields good results, more work is needed to support this.