From June 1991 to April 1993, 25 non-staghorn renal stones with a maximal diameter greater than or equal to 25 mm were treated by piezoelectric extracorporeal lithotripsy (EDAP LT 01). The complete success rate was 56% after 1 (16%), 2 (12%), 3 (16%) or 4 sessions (12%). 14 double J ureteric stents were implanted (56% of cases) and 4 complications were observed (2 cases of acute pyelonephritis and 2 cases of ureteric silting). These results were inferior to those obtained with percutaneous surgery, but help to define the potential indications of extracorporeal shock-wave lithotripsy. This treatment modality can therefore be applied to large friable weddellite or even struvite stones, particularly when the anatomical conditions are unfavourable for percutaneous surgery.