Our initial experience with percutaneous nephrolithotomy in 46 randomly selected patients included 16 who had undergone previous surgery for calculi. A urologist and radiologist cooperated closely in carrying out the procedure, which was performed in one or two stages (16 and 30 cases respectively). Calculi were successfully removed from 80.4% of the patients with the use of grasping forceps or ultrasonic lithotripsy. Operating time ranged from 30 to 180 min and the average hospital stay was 8 days. Complications were few and of a transient nature. Further experience and patient selection is necessary in order to reduce the time and cost of this procedure.