Abstract: Endosulfan, an organochlorine insecticide and acaricide, has been used in agriculture for several years. The aim of present study was to analyze the cardiotoxic effect of endosulfan which caused biochemical changes in heart of male rats and to evaluate the possible protective effect of vitamin E. Vitamin E (200mg/kg, twice a week), endosulfan (2mg/kg per day, once a day in corn oil) and Vitamin E (200mg/kg, twice a week) + endosulfan (2mg/kg per day, once a day in corn oil) combination were given to rats (n=6) orally via gavage for 4 weeks. GPx and CAT activities were measured in tissues samples. Gpx, CAT and SOD activities increased in the endosulfan - treated group heart tissues compared to control group (P<0.01, P<0.05 and P<0.01 respectively). GPx and SOD activities decreased in the endosulfan+vitamin E - treated group compared to endosulfan - treated group (P<0.05). Decrease of CAT activity was not significant in the endosulfan+vitamin E - treated group compared to endosulfan - treated group. We conclude that vitamin E significantly reduces endosulfan - induced oxidative stress in rat heart.