Duodenal perforation in early infancy is an uncommon condition. We describe a case of duodenal perforation from suspected ulcer. A premature boy was born at the gestational age of 26 weeks with a birth weight of 764 g. The Apgar score at 1 min was 3 and at 5 min had decreased to 2. He was given intermittent mandatory ventilation for one month after the birth. Ninety-eight days after birth, the infant's abdomen became distended. A supine and cross-table lateral radiograph of the abdomen revealed massive pneumoperitoneum. An exploratory laparotomy was performed, which revealed two perforations in the anterior wall of the first portion of the duodenum. The operation procedure was direct closure and intra-abdominal drainage. On the postoperative first day, he had central urorrhagia from hematencephalon. The patient's growth after surgery has been normal, with no recurrence of duodenal ulcer.