Purpose: To demonstrate that laparoscopic pyloromyotomy (LP) is less traumatic than the open procedure (OP) for congenital hypertrophic pyloric stenosis (CHPS). Patients and Methods: Seventy-two consecutive cases of LP performed in 1998 through 2000 were compared with 72 consecutive cases of OP done before 1998. The two procedures were compared with multiple clinical parameters including age, body weight, operating time, postoperative antibiotic administration, hospital days, postoperative vomiting, and surgical complications. Laparoscopic pyloromyotomy was performed with a 3.5-mm laparoscope by a three-port technique to complete the pyloromyotomy in situ. The OP was performed through a small supraumbilical crescent incision to do pyloromyotomy by pulling the pylorus out of the abdomen. Results: The mean operating time of LP was significantly shorter than that of OP (24.2 vs. 31.6 minutes). Postoperative antibiotic administration and mean hospital stay were also shorter in the LP group than in the OP group (P <0.01). Vomiting after the operation and surgical complications were less in the LP group. Conclusions: Laparoscopic pyloromyotomy is not only less traumatic but also provides a better view of operative field and better confidence in checking for bleeding and potential perforation. It is preferable in the treatment of congenital hypertrophic pyloric stenosis.