Background:Sildenafil (Viagra) is widely used for the treatment of erectile dysfunction under various etiologies.Unfortunately, chronic administration of sildenafil negatively affects fertility. The aim of the present study is toinvestigate the improvement role of sesame on the testis alterations caused by long-term administration ofsildenafil on albino rats.Results:Light microscopically observations showed that overdoses of sildenafil had provoked tubular andinterstitial histological alterations. Tubular degeneration and abnormality in the germinal epithelium of theseminiferous tubules included spermatocyte degeneration and arrest of spermatogenesis. Sperm count and motilitywere negatively affected by sildenafil. These alterations were improved by sesame feeding.Conclusion:Sesame intake improve the side effects of prolonged treatment with sildenafil significantly. Theseresults demonstrate the pivotal role of sesame that may improve male infertility.