Background: Diuretics increase urine flow and sodium excretion are used to maintain the volume and composition of body fluids in a variety of clinical situations Objectives:  To evaluate the diuretic activity of alcoholic (AERMI) extract of roots of Mangifera indica in albino rats.  Methods: 5 groups of Albino rats were used to evaluate the diuretic activity by using metabolic cages. The group I serves as normal control received vehicle, the group II received Furosemide (10 mg/Kg, p.o) ; other groups III, IV, V were treated with low, medium, and high doses of AERMI and immediately after extract treatment all the rats were hydrated with saline (15 ml/kg) and placed in metabolic cages. Total volume of urine collected was measured at the end of 5 h. Concentration of Sodium, Potassium, Chloride in the urine were estimated. Results: Compared to control group the AERMI at different dose levels (100,200 and 400 mg/kg) has significantly increased the urine volume and also enhanced the elimination of Sodium, Potassium and Chloride. Conclusion: Single dose of AERMI as 100, 200 and 400 mg/Kg and Frusemide have increased the urine output along with an increase in concentration of Sodium, Potassium, and Chloride.