A total of 64 treatments by the Dornier HM3 lithotriptor was performed on 52 solitary kidneys with stones. A slight increase but no significant variations in serum creatinine was noted in 15 patients without obstruction just after treatment (p greater than 0.05). No significant increases in serum creatinine were found even at the short-term, mid-term and long-term followup. After 12 to 56 months hypertension developed in only 1 previously normotensive patient. Of 37 patients at mid-term followup (12 to 24 months) 62% were stone-free, 24% had passable fragments, 8% had recurrent stones and 5% had regrowth of the residual fragments. At long-term followup (24 to 56 months) 50% of 26 patients were stone-free, 19% had dust or passable fragments, 19% had recurrences and 11% had regrowth of the residual fragments. The demonstrated effectiveness, small number of complications at the short-term followup, lack of sequelae at the long-term followup and relatively small number of recurrences confirm that extracorporeal lithotripsy is not only effective but also safe. It can be proposed as the treatment of first choice even when the stone is in a single remaining kidney.