We report a case of rare benign bladder leiomyoma. The patient was a 42-year old man complaining impotence. Digital rectal examination revealed a palpable pelvic tumor. Transurethral ultrasonography, computed tomography (CT), and magnetic resonance image (MRI) examinations all showed a cystic tumor measuring 10 x 8 cm. On the basis of these findings leiomyoma was suspected already before operation. The tumor was removed by open resection of bladder, and the diagnosis was confirmed by histology and positive immunohistochemistry.