10.22376/ijpbs.2019.10.1.p1-12 Volume 4 Issue 3 2013 (July - September) Chlorpyrifos, O,O-diethyl O-(3,5,6-trichloro-2-pyridinol) phosphorothioate, is a broad spectrum moderately toxic organophosphorus insecticide. The widespread use of these pesticides is harmful to the environment and also poisonous to mammals, thus it is essential to remove the same from the environment. In the present study from the chlorpyrifos contaminated soil, six morphologically different bacterial strains were isolated. Among those isolates two bacterial strains which were more efficient were developed as consortium. The two bacterial isolates namely lessThan i greaterThan Pseudomonas lessThan /i greaterThan sp, and lessThan i greaterThan Brevibacillus lessThan /i greaterThan sp present in the consortia were identified on the basis of Bergey's manual of determinative bacteriology. The biodegradation studies of chlorpyrifos (500mg/L) were conducted in neutral pH and temperature 37 °C. During the degradation some metabolites lessThan i greaterThan viz lessThan /i greaterThan ., chlorpyrifos oxon and diethylthiophosphoric acid were identified by mass spectral analysis. The results of merit this consortium is used to remediate chlorpyrifos contamination sites. K.BARATHIDASAN AND D.REETHA Chlorpyrifos, Pseudomonas sp, Brevibacillus sp, LC-MS 1277-1283