Since the deregistration in many countries of most cyclodiene insecticides, the ongoing availability of endosulfan has become important as an alternative option in resistance management strategies of pest species. Additionally, compared to many other available insecticides, it has low toxicity to many species of beneficial insects, mites and spiders (Goebel etc!., 1982). However, endosulfan is extremely toxic to fish and aquatic invertebrates, and it has been implicated increasingly in mammalian gonadal toxicity (Singh and Pandey, 1990; Sinha et al. , 1995; Sinha et al. , 1997; Turner et al, 1997), genotoxicity (Chaudhuri et al., 1999) and neurotoxicity (Paul and Balasubramaniam, 1997). These environmental and health concerns have led to an interest in post-application detoxification of the insecticide. The aim of the research supported by this grant was to isolate an endosulfan-degrading gene as a potential source of an enzymatic bioremediating agent to treat endosulfan contaminated waste water.