In spite of tremendous advances in the field of medicine, there is no truly satisfactory drug for the treatment of renal calculi. In the present study, the efficacy of the root bark of Moringa oleifera Lam. (Moringaceae) as an antiurolithiatic agent was investigated using an experimentally induced urolithiatic rat model. Hyperoxaluria was induced in rats using 0.75% ethylene glycol in water. Aqueous (AqE) (200 mg kg −1 body weight) and alcoholic extracts (AlcE) (200 mg kg −1 body weight) of the root bark of M. oleifera were given orally in curative and preventive regimens over a period of 28 days. Both the extracts significantly (P < 0.001) lowered the urinary excretion and kidney retention levels of oxalate, calcium and phosphate. Moreover, elevated serum levels of urea nitrogen, creatinine and uric acid were significantly (P < 0.001) reduced by the extracts. The results were comparable with the standard drug, cystone (750 mg kg −1 body weight). The reduction of stone forming constituents in urine and their decreased kidney retention reduces the solubility product of crystallizing salts such as calcium oxalate and calcium phosphate, which could contribute to the antiurolithiatic property of root bark of M. oleifera.