A 33-year-old female patient was admitted to our department with bladder tumor. It was detected by a magnetic resonance imaging (MRI) in an examination for hysteromyoma. She had neither hypertention, gross hematuria nor the classic symptoms of cathecholamine excess during micturition. The diameter of the tumor was 33 mm. Cystoscopic examination showed a submucosal tumor in the left anterior wall of the bladder. Percutaneous needle biopsy was performed. Biopsy specimens revealed as a pheochromocytoma. 131 I-MIBG scintigraphy showed abnormal accumulation in the bladder, and no abnormal accumulation in the other lesion. Endocrinologic examination disclosed increased levels of serum and urinary noradrenalin. On May 18, 2005, partial cystectomy was performed. The catecholamine levels normalized after partial cystectomy. The patient has been followed up for 9 months and shown no recurrence.