ABSTRACT We recently performed laparoscopic pyloromyotomy on five patients with infantile hypertrophic pyloric stenosis. In the first case, the pylorus was incised using a Babcock intestinal clamp according to the procedure of laparoscopic pyloric traumamyoplasty reported by Castanon et al. However, the pylorus was restenosed 7 days after operation, and dilation using a balloon catheter was required. In the second case, a seromuscular incision was made by electroendotomy. Firm continuous force was applied to the Babcock clamp until rupture of the hypertrophic muscle was seen and felt. The grooves were produced in one side of the pyloric olive. The Tan pyloric spreader was inserted into the groove of the olive, and the muscle was slit vigorously in the standard fashion. This case has shown an uneventful postoperative course. In the subsequent three cases, the procedure used for the second case was repeated, and the operation was safely accomplished using two ports, in contrast to the three ports used in th...