Cadmium disrupts the blood-testes barrier, interferes with various antioxidant levels thus enhancing lipid peroxidation and ultimately leading to apoptosis and necrosis of testicular tissue. Moringa oleifera is a medicinal plant and a rich source of essential phytochemicals possessing antioxidant properties. The effect of aqueous leaf extract of M. oleifera on reproductive function following cadmium chloride induced oxidative stress in male Wistar rats was investigated. Forty adult male Wistar rats were assigned into five groups of eight rats each. Treatment was administered orally daily as follows: Group 1 (control): animal feed and tap water ad libitum; Group 2: 5 mg kg-1 cadmium chloride for 21 days; Group 3: 500 mg kg-1 of M. oleifera and 5 mg kg-1 of cadmium chloride for 21 days; Group 4: 5 mg kg-1 cadmium chloride for 21 days followed by 500 mg kg-1 M. oleifera for the next 35 days; Group 5: 5 mg kg-1 cadmium chloride for 21 days followed by 750 mg kg-1 M. oleifera for the next 35 days. At the end of treatment, blood was obtained by direct cardiac puncture for fertility hormone assay and testicular tissue specimens were harvested for semen analysis and determination of antioxidant levels. Results obtained indicated that rats treated with the various extracts had significantly increased superoxide dismutase, malondialdehyde and catalase levels, increased serum concentrations of testosterone, follicle stimulating hormone and luteinizing hormone and increased percentage of viable and normal spermatozoa compared to control and only cadmium chloride treated rats (p < 0.05). The results obtained suggest that treatments with M. oleifera extract could ameliorate possible cellular damage caused by administration of cadmium chloride.