The purpose of this study is to evaluate the applicability of intravenous atropine sulfate therapy in infantile hypertrophic pyloric stenosis (IHPS). From 1998 to 2000 among 35 cases of IHPS, pyloromytomy was performed in 13 (Group A), and intravenous atropine was given as a primary therapy in 22 cases (Group B). In group A, all cases were cured completely. In group B, 13 (59 %) out of 22 cases were successfully treated with atropine, but 9 were failed therapy, and required operation. The recovery period to normal feeding and the hospital stay of the successful atropine group were longer than those of pyloromyotomy, 8.6 days vs. 2.9 days and 13.2 days vs. 4.1 days, respectively. In conclusion, intravenous atropine therapy did not replace pyloromyotomy, but it might be an alternative for the selected patients with contraindications for operation.