Introduction. Gastric perforation in newborns is a polyetiological, severe disease that combines a number of destructive conditions, such as: isolated pinpoint perforations, wall necrosis and gastric rupture. The first description of this pathology in a premature infant was made by Siebold in 1825, and only in 1968, G. Reams reported a case of successful diagnosis and surgical correction of this disease. Currently, the frequency of gastric perforation occurs from 1 to 6 cases per 30 thousand live births, and the mortality rate is within 40–70%.In all infants, disorders in the integrity of stomach wall can be divided into iatrogenic and “idiopathic” which are caused, in most cases, by intrauterine hypoxia. Therefore, while examining such patients, differential diagnostics between gastric perforation and necrotizing enterocolitis is often made.Clinical case. The authors present their experience in diagnosing and treating segmental necrosis of the stomach and duodenum outlet in a child with an extremely low body weight of 800 gr. Predisposing factors in the antenatal period were considered to be manifestations of hereditary thrombophilia, severe preeclampsia, placental insufficiency, and intrauterine growth retardation. As far as the discussed pathology had a subacute course, clinical changes were registered only on the 21st day of infant’s life, when pneumoperitoneum was detected at the plain X-ray image. When the patient’s condition was stabilized, median laparotomy was performed, at which radial necrosis with detachment in the gastroduodenal junction was seen. An end-to-end gastroduodenoanastomosis was put at the defect zone. In the postoperative period, the course was complicated with bronchopulmonary dysplasia, oblique femoral fracture with angular fragment displacement because of premature osteopenia as well as cholestatic hepatitis. The patient was discharged from the hospital in satisfactory condition in 80 days.Conclusions. Thus, better understanding of specific features in the clinical picture of the discussed pathology and of the mechanisms of perforation development in hollow organs of the abdominal cavity will reduce the number of complications and adverse outcomes in patients with extremely low body weight.