• Urinary calculi occurring in postpoliomyelitic patients in respirators present important problems of prevention and treatment. No dependable methods of prevention have been developed; methods of treatment may be classified as either conservative or surgical. The possibilities of conservative treatment are illustrated in the case of a 9-year-old girl with bilateral obstruction by ureteral calculi; after cystoscopy and bilateral ureteral catheterization, the calculi passed down the ureters over a period of three weeks and were eventually passed by the urethra with minimal symptoms. Details are given of two other cases in which surgical treatment became necessary. Major urologic surgery in the renal fossa was performed successfully seven times in five patients. The lateral nephrectomy position was used; it was formerly thought that these patients would not tolerate this position. Resection of the 12th rib facilitated the approach to the kidney. Since much of the patient's muscle is replaced by fibrous tissue, dissection may be hard and hemostasis requires special attention. The use of the endotracheal tube during anesthesia, of special forms of respirators, of induction with thiopental given intravenously, of antibiotics, and of the nasogastric tube to prevent gastric dilatation, all contributed to the success of the surgery, which these patients tolerated surprisingly well.