Over a 34-month period, 51 open and 33 laparoscopic pyloromyotomies were performed for infantile hypertrophic pyloric stenosis. The patients' weight ranged from 1.2 to 5.3 kg. The mean operating time was 28 minutes for the open group and 41 minutes for the laparoscopic group. The average time to accept normal feeds was 41 hours in the open group and 32 hours in the laparoscopic group. There were three perforations, one inadequate pyloromyotomy, and one wound infection in the open group. In the laparoscopic group one patient underwent conversion to open surgery because of a duodenal perforation and three other patients required subsequent open procedures for duodenal perforation (n = 1), pyloric perforation (n = 1) and inadequate pyloromyotomy (n = 1). Additional complications in the laparoscopic group included two cases of omental extrusion through the umbilical port wound and one suture abscess. On the basis of these results we have modified our technique, and there have been no complications after laparoscopic pyloromyotomy in our last 10 patients. We believe laparoscopic pyloromyotomy requires further evaluation before it is accepted into common practice.