A statistic analysis was carried out on the 4,956 inpatients admitted to our Department of Urology from April 1972 to December 1991. The patients included 3,399 males and 1,557 females. A total of 4,105 operations including 255 renal allotransplantations were performed on 3,590 patients. Open surgery for upper urinary tract stones has been replaced by extracorporeal shock-wave lithotripsy (ESWL) in the last three years.