The onset of hypertrophic pyloric stenosis in the postoperative course of esophageal atresia with tracheoesophageal fistula is rarely reported. The diagnosis could be delayed due to its mimicking symptoms of other postoperative complications including gastroesophageal reflux or anastomotic stricture. We present an infant who had surgery for esophageal atresia with tracheoesophageal fistula. He had never fed since birth. The infant presented with an increased amount of orogastric tube drainage and consistently distended gastric air on simple abdominal X-ray. Abdominal ultrasonography showed hypertrophic thick pyloric muscle. The diagnosis of pyloric stenosis was confirmed d is rarely reported. The diagnosis could be delayed due to its mimicking symptoms of other postoperative complications including gastroesophageal reflux or anastomotic stricture. We present an infant who had surgery for esophageal atresia with tracheoesophageal fistula. He had never fed. The infant presented with uring surgery. After pyloromyotomy, the patient's condition improved.