The impact of different atrazine concentration on a chitinolytic actinomycete and the biodegradation of atrazine by this microbe was examined.Isolates were grown in pure culture in Chitin Mineral Salts Broth with and without addition of atrazine for a two month incubation at room temperature on a rotary shaker. Visual observations, analysis by High Performance Liquid Chromatography (HPLC) and radioisotope methodology were used to determine this impact on chitinolytic activity. Analysis by HPLC and Gas Chromatography with Electron Capture Detector (GC with ECD) were used to determine the breakdown of atrazine.No atrazine derivatives were determined by HPLC and GC analysis. Only the 0.1 ppm atrazine concentration with the actinomycete culture demonstrated tolerance to the atrazine and showed chitinolytic activity in the radioactive assay and chitin derivatives by HPLC. SEM and TEM work determined that the actinomycete was actually a Streptomyces sp. / Department of Biology