Rubia cordifolia Linn. (family: Rubiaceae) is known as Indian madder. The present investigation was carried out to evaluate the diuretic activity of the hydroalcoholic extract of roots of Rubia cordifolia in rats to support its folklore claim. Roots of Rubia cordifolia was coarsely powdered and extracted using 70% ethanol with soxhlet extractor for 22h. Four groups of rats were treated with vehicle (normal saline: 25 ml/kg), furosemide (20 mg/kg) and two doses of extract (286 mg/kg and 667 mg/kg body weight) orally. Urine excreted was collected up to 5h post-treatment and analyzed for urine volume, Na+, K+, Cl- and creatinine content. The extract showed a significant (p<0.01) and dose dependent increase in urine volume and electrolyte excretion. Both doses of extract showed less influence on creatinine clearance than furosemide. The result indicates that hydroalcoholic extract of roots of Rubia cordifolia possess potent diuretic activity.