In this study, the effect of low-dose curcumin on sperm parameters, reproductive hormones, lipid profile, biochemical antioxidant parameters and the histopathological structure of the testis in diabetic male rats were evaluated. In the study, 28 male Wistar albino rats weighing 300-370 g and aged 8-10 weeks were used. Four groups of equal numbers have been created. Diabetes mellitus was induced with 45 mg/kg streptozotocin (STZ) in seven rats. Curcumin was administered to the rats in curcumin and the diabetes + curcumin group by gavage for 15 days at a dose of 10 mg/kg. Then, the rats were sacrificed. Blood samples and testis tissues were obtained, while the rats were under anaesthesia. Glucose, lipid profile, reproductive hormones, sperm parameters, biochemical antioxidant parameters and histopathological examination of the testis were performed. Abnormal sperm ratio, malondialdehyde, glucose, cholesterol, low-density lipoprotein, and triglyceride levels and caspase-3 expression were increased in diabetic rats, while the sperm motility and intensity and reduced glutathione, catalase and testosterone levels were decreased. When low-dose curcumin (10 mg/kg) was administered to diabetic rats, we found that curcumin significantly increased sperm motility and density, and decreased abnormal sperm rate according to the diabetic group. Moreover, curcumin significantly suppressed the lipid profile and increased follicle-stimulating hormone (FSH) and testosterone levels compared to the diabetic group. On testicular damage and decreased reproductive hormones caused by diabetes, curcumin may have a protective effect with indirect effect of glycaemic control by curcumin.