A total of forty adult Sprague-Dawley male rats were used to study the ameliorative effects of moderate exercise on reproductive function in male rats doped with a high dose of anabolic steroids. Rats were randomly assigned into 4 groups; sedentary, sedentary doped (I/M 25 mg/kg BW per week), moderately exercised (20 minutes/day for five days every week along one month) and moderately exercised doped groups. The results clarified that the moderate exercise significantly increased sperm motility (91.67%±1.67); live sperm and sperm count percentages (93.33%±1.67 & 115.33%±7.51 respectively) and lowered sperm abnormalities (11.0±3.61). On contrary, doping induced via testosterone administrations in both sedentary and moderately exercised rats significantly decreased the previously mentioned sperm parameters (63.33%±3.33, 53.33%±3.33 & 65.33%±9.45 respectively) while increasing sperm abnormalities (53.33±11.50); although amelioration via exercise was noticed in these parameters. Serum free testosterone levels were significantly increased with both sedentary doped or moderately exercised doped groups. Moreover, superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) activities were significantly elevated with moderate exercise (52.05±6.67, 39.25±7.09 and 69.17±7.69 respectively). While, malondialdehyde (MDA) levels were increased with doping of male rats (86.5±9.99). Furthermore, StAr gene expression was significantly (P≤0.01) up-regulated with moderate exercise and significantly (P≤0.01) down-regulated with doping of male rats. In addition, HSD17B3 gene expression was significantly (P≤0.01) up-regulated in both moderately exercise and moderately exercise doped groups. On contrary, HSD17B3 gene expression was significantly (P≤0.01) down-regulated in sedentary doped group Overall, these results suggest a beneficial and protective effect of moderate treadmill exercise on male fertility especially in steroid abuse models.