Piezoelectric shock wave lithotripsy has been shown to offer a low-cost, safe, anesthesia-free yet effective means of disintegrating urinary calculi. The Therasonic lithotriptor combines proprietary piezoelectric shock wave technology for effective stone fragmentation with a multi-purpose urologic table and both fluoroscopic and ultrasound imaging for accurate stone localization and real-time treatment monitoring. From December 1, 1988 to November 15, 1989, 138 patients with 172 calculi were treated (94.2% were intrarenal, 5.8% were in ureter). All stones greater than or equal to 4 mm were considered suitable for treatment. Lithotripsy was performed under intravenous sedation except when ancillary procedures were necessary. For evaluation of device effectiveness, 94 patients were available with follow-up greater than or equal to thirty days. Successful fragmentation (stone free or residual debris less than or equal to 4 mm) was achieved in 97 percent of patients. The retreatment rate for stones 0.5-2.0 cm was 11 percent, and the overall retreatment rate was 21.2 percent regardless of stone size. Complications were minimal, transient, and resolved spontaneously.