In this study, we aimed to evaluate the outcome of patients with renal stones who had undergone percutaneous nephrolithotomy (PNL) in our clinic. Between April 1999 and February 2002, 50 PNL procedures were done in 47 patients (27 male, 20 female) with a mean age of 41.8 (16-69) years. The mean stone size was 2.9 (2 to 4.5) cm and mean stone area was 602 (240 to 1575) mm2. Three patients had bilateral renal stones and they were treated with bilateral single session PNL. PNL procedure was performed from single renal tract in 40 patients while more than one tract was needed for 7 patients. A nephrostomy catheter was placed in all cases after clearing the stones. The catheters were removed in postoperative 1st or 2nd day. The mean follow-up period was 13 months (3-34). At 3rd month of treatment all patients were re-evaluated with plain film or IVP, blood creatinine level, urine analysis and culture. The mean operation time was 180 minutes (120-270). While 36 of 47 patients (77%) become stone free, residual fragments smaller than 4 mm were remained in 7 patients (15%). When these fragments were defined "clinically insignificant" the overall success rate raised to 91% (43/47). Residual stone(s) in size 4-10 mm were remained in 4 patients. ESWL was performed to these patients one month after the PNL procedure. Peroperative hemorrhage requiring transfusion was encountered in 3 patients (6%). No major complication was observed during or postoperative period. The mean hospitalization period was 2.6 (1-4) day. At 3rd month, 45 patients (96%) were stone free. PNL, that has a high success rate when combined with ESWL, is a safe and effective treatment option for stones bigger than 2 cm with low complication rate and rapid recovery time.