Protective effects of standardised extract of Costus afer leaves (CAME), an extract with good antioxidants on cadmium-induced reproductive toxicity in male rats, were investigated in this study. Forty-two adult male Wistar rats were randomly divided into six groups and were treated every day regularly for 4 weeks. G1 (control) rats received 1 ml of vehicle treatment. G2 rats were intoxicated with 2.5 mg kg  day s.c cadmium chloride for 1 week. G3 and G4 rats were intoxicated with cadmium as in G2 rats and were treated orally with 100 and 200 mg/kg bwt/day of CAME, respectively, for 4 weeks. Group G5 and G6 rats were orally treated with 100 and 200 mg kg  day bwt of CAME, respectively, for 4 weeks. Significant changes (p < 0.05) in andrological parameters (sperm count, sperm morphology, serum testosterone and nitric oxide concentration) and testicular antioxidant parameters (reduced glutathione, lipid peroxidation and activities of catalase, glutathione S-transferase and glutathione peroxidase) caused by Cd toxicity were improved in cadmium-intoxicated rats treated with 100 mg/kg body weight of CAME. Administration of 200 mg/kg body weight of CAME to cadmium-intoxicated rats potentiated reproductive toxic effects of cadmium. In conclusion, lower dose of CAME is preferred over high dose in treatment of cadmium-induced reproductive toxicity in rats.