Abstract: Pheochromocytoma of the urinary bladder is a rare tumor. Up to 1988, 145 cases have been reported in the literature and more than 30 cases in our country. Mostly are case reports. In our hospital, we have collected 7 cases among 2065 bladder tumors （0.34%） and studied them with light and electron microsopy and by immunohistochemical staining. According to the clinical features 5 of the lesions are classified as non-functional tumors. In this paper the causes of misdiagnosis in these cases are dercribed and histological differential diagnoses are discussed.