Malignant lesions of the bladder in infancy and early childhood arise from mesenchymal tissue. Among the mesenchymal tumors embryonal rhabdomyosarcoma is more common in young children than in adults. The gross appearance of rhabdomyosarcoma of the bladder is typically that of polypoid grapelike clusters of tissue, termed "sarcoma botryoides". Histologically, the lesion is consistent with embryonal rhabdomyosarcoma. The growths originate in the submucosal layer of the trigone and the internal urethral orifice. Rhabdomyosarcoma (RMS) of the bladder in children tends to remain within the disease. Deep extension and metastasis to regional lymph nodes and to distant sites is a relatively late occurrence. The symptoms are characteristically those of obstruction and strangury. Hematuris is uncommon. The intravenous urogram shows characteristic lobulated filling defects. Treatment of choice is almost always total cystectomy. Suprapubic cystotomy must be prohibited both as a method of drainage and as an approach for biopsy since tumors ulcerating through the abdominal wall after cystotomy and local excision have been observed. With concomitant administration of radiation therapy in selected cases and the combination of surgery with multiple drug chemotherapy, promising results have been obtained in the therapy of embryonal RMS of the bladder in children.