Foveolar cell hyperplasia (FCH) has been reported as a rare cause of persistent gastric outlet obstruction in patients with infantile hypertrophic pyloric stenosis (IHPS), which, if present, requires excision of the gastric foveolar folds to resolve the persistent obstruction. This is a review of patients with IHPS diagnosed on abdominal ultrasound to determine the incidence of FCH in IHPS and to evaluate whether it has a causal role in postoperative vomiting following pyloromyotomy for IHPS.