Duodenal perforation in neonates is a very rare entity. Gastrointestinal perforation withwout obvious etiology has been labeled as idiopathic or spontaneous. A neonate of idiopathic duodenal perforation without pneumorperitoneum is presented. A full term male neonate presented with persistent abdominal distension at 3 days of age. Although he received conservative treatment, abdominal distension became worsened gradually. Abdominal sonography was performed at 10-day-old and meconium peritonitis was suspected. He received exploratory laparotomy and a doudenal peroration was found. The perforated hole was treated by primary closure. The recovery course of this patient was unventful. He began oral feeding on the 5th day after surgery and was discharged on the 10th day.