Abstract Purpose: The aim of present study was to investigate the effects of endurance training on adiponectin, sex hormones, and sperm parameters in Streptozotocin–Nicotinamide induced diabetic rats. Methods: In this experimental study, 36 eight-week-old Sprague Dawley rats (200-250 g) were randomly assigned into three groups: healthy control, diabetic control, and diabetic endurance training. Diabetes was induced by intraperitoneal injection of nicotinamide solution (120 mg/kg) and STZ solution (65 mg/kg). One week after STZ injection, the endurance training protocol was performed for ten weeks. Twenty-four hours after the last training session, left epididymis of each rat was dissected to measure sperm parameters. Finally, blood serum was used to assess follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone, and adiponectin levels. Data were analyzed using one-way ANOVA at 0.05 level of significance. Results: Results showed that after 10 weeks of endurance training, there was a significant decrease in fasting blood glucose levels of diabetic endurance training group compared to diabetic control group (p=0.013). There was also an increase in serum adiponectin levels so that no significant difference between endurance training group and healthy control group was observed (p=0.423). In addition, endurance training induced significant increases in serum testosterone (P=0.000), LH (P=0.002), and FSH (P=0.029) levels in the diabetic endurance training group in comparison to the diabetic control group. Sperm parameters in the diabetic endurance training group including sperm count (P=0.05) and sperm motility (P=0.041) presented significant differences compared to diabetic control group, but the differences for sperm viability (p=0.089) and sperm morphology (p=0.684) were not significant. Conclusion: Short term endurance training can improve serum adiponectin levels and sperm parameters, including sperm count and sperm motility through increasing seru
