Pheochromocytoma originates from chromaffin cells and occurs in the adrenal medulla in majority. About 10 percents of pheochromocytomas can occur in extra- adrenal sites, and anywhere along the fetal route of chromaffin tissues, Pheochromocytomas involving the urinary bladder are rare neoplasms which probably account for less than 0. 06% of all bladder tumors. A characteristic symptom complex due to increased catecholamine release in association with detrusor activity during micturition is often the essential element required for the diagnosis of this rare lesion. However, the diagnosis is often delayed for many years, because most physicians are unfamiliar with the symptoms, due to the rarity of this neoplasm. We report two cases of functioning pheochromocytoma of the urinary bladder with typical symptoms. The tumors of patients were explored transperitoneally and removed by partial cystectomy.