From early 1982 to December 1985, 317 patients underwent 346 transurethral ureteroscopic procedures at our institution. For most patients the intramural ureter was dilated with balloon dilators and all procedures were performed under fluoroscopic control. The over-all success rate for lower ureteral stone removal was 95 per cent, which increased to 97 per cent for stones treated in 1984 and 1985. Ureteroscopy is useful for the evaluation of idiopathic gross hematuria, and for the diagnosis and treatment of ureteral and renal pelvic tumors. The over-all mean hospital stay was 4.9 days and the procedure has been a significant addition to our armamentarium.