Abstract This study was performed to assess the effect of deltamethrin (DLM) insecticide on male fertility in rats and to examined the possible protective role of vitamin E. Twenty five sexually mature male rats were randomized into 5 groups; one group was kept as a negative control. In the remaining 4 groups, DLM was orally administered at doses 6 and 3 mg kg-1 (corresponding to 1/10 and 1/20 of LD50) b.wt alone and / or in combination with vitamin E, for 65 days. Blood samples were withdrawn for determination of testosterone, FSH and LH in the serum. Semen analysis, Sex organs weight, antioxidant (superoxide dismutase, SOD; Glutathion peroxidase and Catalase, CAT) enzyme activities in testicular tissue and histopathological changes in testes were evaluated. The results showed that concurrent administration of vitamin E with DLM improved the relative weight of testes and increased sperm cell concentration and percentage of sperm motility and viability. There were also significant increases in serum testosterone, FSH and LH levels and antioxidant enzymes activity in testes, associated with amelioration of testicular degenerative changes.In conclusion, vitamin E exerts a protective effect against testicular toxicity induced by DLM in male rats.