Ultrasound is ideally suited for imaging of renal calculi for extracorporeal shock wave lithotripsy. Ultrasound can localize radiolucent stones, monitor fragmentation in real time, and differentiate the stone from a stent. Its use significantly reduces the radiation exposure to patient and operator, which is particularly desirable in the pediatric patient. Furthermore, sonography-guided lithotripsy can reveal any incidental finding in the affected kidney that may require further evaluation and familiarizes the operator with this increasingly useful imaging method. The ultrasound-guided Sonolith 3000 with its enlarged ellipsoid aperture has a decreased energy focus size and voltage, permitting fragmentation with reduced anesthesia requirements. The initial extracorporeal shockwave lithotripsy (ESWL) machine, the Dornier H3, uses fluoroscopy for stone localization and treatment monitoring. Although this imaging method has the benefit of being familiar to urologists, it has some drawbacks, such as difficulty in imaging some types of stones and the radiation exposure of the operator and the patient. We have been using the Technomed Sonolith 3000 ESWL machine, which uses ultrasound to localize stones. During this experience, we have found a number of obvious and not so obvious benefits. For example essentially all calculi are echogenic, irrespective of their radiologic density. Moreover, with ultrasound, fragmentation can be monitored by real-time imaging, making determination of the treatment end point easier, and the stone and stent can be differentiated clearly. Ultrasound also can reveal other pathology and eliminates radiation exposure. Moreover, an ultrasound-guided ESWL unit familiarizes the operator with ultrasound techniques, and the same machine can be used for biliary lithotripsy. All of these features make ultrasound imaging for ESWL desirable.