PURPOSE To assess the safety and effectiveness of pure ultrasound-guided percutaneous nephrolithotomy. PATIENTS AND METHODS Three hundred fifty-seven patients were treated; 139 women and 218 men, with a mean age of 33.7 years (range 21-69 years) and a mean stone size of 33.5 mm in maximum diameter (range 20-52 mm). Stone locations were renal pelvis (174), lower calyx (68) or both (115) with mild to moderate hydronephrosis seen on excretory urography. A ureteral stent was inserted by cystoscope, and saline was injected for better localization of the pelvicaliceal system (PCS), if needed. Puncture of the PCS was done by an 18-gauge nephrostomy needle through the lower pole calyx, and all the steps, including dilatation, were done under the guidance of ultrasonography. RESULTS The day after the operation, 318 (89.07%) patients were stone-free in the kidneys, ureters, and bladder x-rays. Nineteen patients (5.3%) had multiple fragments that measured equal or less than 5 mm and passed them spontaneously in 2-4 weeks (total stone-free rate 94.4%). Access failure occurred in ten obese patients (2.8%) and fluoroscopy was required. Residual fragments with sizes of 10-12 mm were seen in seven patients, all of who underwent shock wave lithotripsy. In one patient, a fragment measuring 7-8 mm migrated into the distal part of the ureter. It was fragmented with ureteroscopy and pneumatic lithoclast 2 days after the operation. In two patients who had large (>15 mm) residual stone redo percutaneous nephrolithotomy was performed 48 h after the first procedure. CONCLUSION Percutaneous nephrolithotomy guided by ultrasonography seems to be as effective as fluoroscopy in selected cases and poses no risk of surgeon and patient exposure to radiation; however, more experience is required.