Pregnant rats were exposed to endosulfan (1 or 2 mg/kg per day) from day 12 of gestation through parturition. Male neonates were fostered to untreated dams. At 100 days of age, the male offspring were sacrificed. Exposure to endosulfan during fetal gonadal differentiation altered the process of spermatogenesis by affecting testicular lactate dehydrogenase and sorbitol dehydrogenase. Reduction in spermatid count in testis and sperm count in cauda epididymis was observed. Testis, epididymis and seminal vesicle showed significant decrease in weights in both the treated groups while no effect on prostate weight was recorded. Hence it can be suggested that endosulfan interferes in the process of spermatogenesis. The overall toxicity was dose dependent.