Two patients with renal pelvic stone in a horseshoe kidney who underwent a percutaneous nephrolithotripsy (PNL) are presented. Case 1 was a 36-year-old man with a 20 x 12 mm right renal pelvic stone in a horseshoe kidney. Case 2 was a 47-year-old man who had been followed up at our clinic for a horseshoe kidney and was found to have a 15 x 10 mm left renal pelvic stone. We found that percutaneous removal of renal pelvic stones can be performed safely in a horseshoe kidney. It appears that to remove stones from the renal pelvis in a horseshoe kidney 4 items must be considered. 1) The anatomical relationships of the horseshoe kidney to other viscera and blood vessels should be confirmed before surgery utilizing computerized tomography or ultrasound sonography. 2) The occlusion ureteral catheter should be inserted up to the renal pelvis to prevent small fragments from falling into the ureter. 3) The rigid nephroscopy should be introduced through the most appropriate calyx, so that its manipulation could be limited. 4) The fragmentation of stones should be performed from the peripheral surface of a stone to prevent from migrating into another calyx. We believe this is only the sixth and seventh documented cases involving a horseshoe kidney.