Aerobic bacteria degrading endosulfan were isolated from contaminated sludge.One of the isolates,LD-6,was identified as Stenotrophomonas sp.The bacterium could utilize endosulfan as the sole source of carbon and sulfur.100 mg/l endosulfan was completely degraded within 10 days,and endosulfan diol and endosulfan ether were detected as major metabolites with a slight decrease in culture pH.The results indicated that S.sp.LD-6 might degrade endosulfan by a non-oxidative pathway.Biodegradation of both isomers was relatively better at a temperature range of 25-35℃,with a maximum at 30℃.In addition,cell crude extract of strain LD-6 could metabolize endosulfan rapidly,and degradative enzymes were intracellular distributed and constitutively expressed.Besides,application of the strain was found to promote the removal of endosulfan in soil.This study might help with the future research in better understanding of the biodegradation.