We present a rare case of bladder leiomyoma with an unusual presentation as a pelvic mass. Bladder leiomyomas are very rare tumors, compromising less than 0.43% of all bladder tumors. Magnetic resonance imaging showed a 16 x 13 cm mass covering the entire pelvis and extending up to the umbilicus. There was a 20 x 20 x I I cm immobile mass originating from the bladder at laparotomy. The mass was removed by bladder-sparing surgery and was reported to be leiomyoma. We conclude that bladder leiomyomas should be preoperatively recognized as a cause of pelvic mass in order to make the possible diagnosis.