Urolithiasis in pediatric patients is relatively rare. Extracorporeal shock wave lithotripsy and endoscopic procedures play a major role in treating pediatric urolithiasis. A 3-year-old girl presented with macroscopic hematuria and right back pain and was diagnosed with a right renal stone (15 mm). Obstruction of ureteropelvic junction was suspected on computed tomography-urography and therefore the patient underwent percutaneous nephrolithotripsy (PNL). The operation was performed using a 12 Fr miniature nephroscope and Ho : YAG laser without any complications. This patient achieved a stone-free status. The stone analysis revealed a mixture of calcium oxalate and ammonium acid urate. PNL with a miniature nephroscope is safe and effective treatment for pediatric urolithiasis.