We herein describe a new technique to improve the ultrasonic imaging of nonobstructed stone-bearing kidneys. Mannitol-induced diuresis opens up the collapsed renal collecting system and yields better ultrasonographic imaging by increasing the amount of fluid surrounding the calculi. The potential usages of this technique include ultrasound localization for percutaneous stone extraction and during ultrasonographic monitoring of stones treated by extracorporeal shock-wave lithotripsy (ESWL).