Between October 1990 and April 1996, we treated 892 upper urinary tract stones with ESWL therapy using Lithostar (Siemens Medizinische Technik, Erlangen, Germany). In March 1993, the coupling head of lithotriptor was upgraded from "standard-tube" to "C-tube". The C-tube has approximately two times or more destructive energy and intensity than the standard-tube. In this study, we analyzed the clinical results according to type of coupling head in 713 cases treated by ESWL monotherapy and evaluated 3 months after the initial treatment. The overall success rate at 3 months after ESWL was 85% in the standard-tube cases and 93% in the C-tube cases; the stone-free rate was 72% and 82%, respectively. There were no cases in which had to be discontinued due to ESWL severe side effects. However, in 66.1% of the C-tube cases and 31.1% of the standard-tube cases, a sufficient destructive intensity could not be used because of pain. Within a group that received sufficient destructive intensity, the C-tube was able to reduce both duration of the procedure and the number of shots to two thirds of that of the standard-tube.