Organochlorine Pesticides (OCPs) were analyzed using Gas Chromatography-Mass Spectrometer (Selective Ion Monitoring mode) in the muscle tissues of five fish species such as O. mossambicus, L. parsia, E. suretensis, C. striata and S. wynaadensis from seven locations of River Cauvery and one location in Veeranam Lake. OCPs viz., DDTs, HCHs, CHLs, cyclodienes, heptachlor, HCB and mirex were detected with varying concentrations among species and locations. Mirex which was not reported in the fish tissues elsewhere reported in this study. The study on the risk associated with the consumption of fish species that had higher concentrations of aldrin, dieldrin and mirex showed significant carcinogenic risk to the human beings.