We report an unusual case of a leiomyosarcoma of the urinary bladder after chemotherapy for retinoblastoma and the results of a review of the published reports of bladder sarcomas. A 22-year-old man presented with hematuria and was found to have a mass in his urinary bladder on computed tomography. Transurethral resection of the mass revealed a leiomyosarcoma. The patient underwent radical cystectomy and an ileal conduit was created. The final pathologic examination confirmed high-grade leiomyosarcoma. Prospective randomized combination trials similar to the Intergroup Rhabdomyosarcoma Study in the pediatric population are necessary to better understand and manage these potentially curable sarcomas.