Perforation of the urinary bladder without history of antecedent trauma is a rare clinical occurrence in children, but should be considered in patients with voiding disorders, abdominal symptoms and unexplained metabolic disturbances. The present report concerns a young infant who presented with irritability, abdominal colic, decreased urine output; blood examinations showing mild leukocytosis, azotemia and metabolic acidosis. Further cystogram and cystoscopy confirmed rupture of the bladder. She had an uneventful recovery after a twelve days of conservative treatment with indwelling catheterization and nutritional support. A subsequent urogram revealed complete healing of the lesion.