Introduction : Pylorospasm is one of the cause of delayed gastric emptying in infants. Most pylorospasm patients present with projectile vomiting as in patients with hypertrophic pyloric stenosis (HPS). But pylorospasm is different from HPS because there is no persistent stenotic lesion and it can be treated conservatively with watchful waiting. Antispasmodics has been proposed as a treatment for pylorospasm, but its use in neonates has been rarely reported. We present a case of pylorospasm diagnosed in neonatal period and treated successfully with intravenous (IV) atropine. Case : A 3180g male infant was born outside hospital at 38weeks 3days of gestational age. He showed marked abdominal distension from the first day of life, and he was referred to our hospital because the distension did not improve with 6 days of gastric decompression. Ultrasonography and gastrointestinal (GI) fluoroscopy showed no stenosis or hypomotility, but only segmental dilatation of small intestine. The resection of dilated bowel and ileostomy were performed at 10 days of age. Ganglion cells were present in all tissues obtained from biopsies. One week after the surgery, enteral feeding was tried but was soon stopped because of the repeated vomiting. From serial imaging studies, he showed only mild gastric distension. Despite careful feeding increase, residual milk remained above 80% each time we examined the gastric juice. Follow-up GI fluoroscopy showed the restricted muscle relaxation at pylorus, so he was diagnosed with pylorospasm. As the symptom did not improve during 3 weeks of conservative care, we started the administration of IV atropine to improve spasmodic movement of pyloric muscles at a dose of 0.06mg/kg/day, and then maintained it at 0.12mg/kg/day from the next day. Delayed gastric emptying was gradually improved and atropine infusion continued for 3 weeks. There was no clinical adverse effect from medication. After discharge, he didn’t show any eating problem and is currently in normal growth at the age of 18 months. Conclusion : This is the first neonatal pylorospasm case in Korea. As shown in this case, patients with delayed gastric emptying should undergo evaluation with the suspicion of pylorospasm. For the pylorospasm that is not responding to conservative care, IV atropine would be good treatment option.