A modified technique of laparoscopic pyloromyotomy was used to treat infantile hypertrophic pyloric stenosis. Introducing a 5-mm periumbilical port for visualization, two stab wounds are made on either side laterally to directly insert 2.7-mm instruments for manipulation. From the left, the stomach is grasped - not the duodenum! From the right, an inexpensive disposable arthroscopy knife is used to incise the serosa and begin the myotomy, which is completed with a laparoscopic spreader until the muscle is separated sufficiently to relieve the obstruction. Twenty-nine children treated with laparoscopic pyloromyotomy were compared to 125 children treated with the conventional open Ramstedt pyloromyotomy. There were no statistically significant differences in the presentation or results between groups, suggesting that the laparoscopic technique is a safe and equal alternative.