Oxidative tress is known to play an important role in the pathogenesis of diabetes. Resveratrol has antioxidant and antidiabetic effects. This study purposed to evaluate the protective effect of resveratrol against testicular injury in streptozotocin-induced diabetic rats. Twenty four male Sprague Dawley rats were randomly divided into four groups: control, Resveratrol (RSV), Diabetes (DM) and DM+RSV groups. DM group was induced by a single intraperitoneal (i.p.) injection of streptozotocin (60 mg kg-'). RSV and DM+RSV groups were administered 20 mg kg(-1) resveratrol i.p. per day. All rats were sacrificed at the end of the 14th day. Testis tissues and blood samples were collected for biochemical and histopathological examination. At the end of the 1st and 2nd weeks, blood sugar levels rose significantly in. the DM and DM+RSV groups. These levels also decreased significantly in the DM+RSV group compared to the DM group. Tissue malondialdehyde levels rose significantly in the DM and DM+RSV groups, compared to the control and RSV groups and decreased in the DM+RSV group compared to the DM group but this decrease was not significant According to Johnsen's tubular biopsy scoring, spermatogenesis decreased in the DM group, increased in the DM+RSV group compared to the DM group significantly. Apoptotic index in seminiferous tubule cells increased in the DM and DM+RSV groups compared to the control group and decreased in the DM+RSV group compared to the DM group significantly. The findings show that DM increases oxidative stress and testicular damage. RSV protects DM-induced oxidative testicular damage at the histopathological and apoptotic level, in particular by reducing blood sugar levels.