Doppler sonography and B-mode ultrasound scanning have been used to perform nephrotomies without circular arrest of the kidney in 107 renal lithotomies. Between 1 and 12 nephrotomies were performed on a single kidney. Average duration of the operation was 270 minutes. The blood loss varied between 20 and 4,500 ml. Three patients required a short period of pedicle clamping. The residual stone rate was 7.5 per cent. Of 9 complications 2 are attributable to the surgical technique. Late follow-up studies in 14 patients showed a 10 per cent improvement of kidney function.