BACKGROUND: Hepatic portal venous gas (HPVG) is a rare imaging finding in children. It can be an important manifestation of severe diseases such as necrotizing enterocolitis (NEC) in neonates or bowel wall rupture in older children. However, there are many other diseases presenting with HPVG that do not necessarily require a surgical intervention. CASE REPORT: In the period between 2011-2015, there were 12 cases of HPVG in children aged up to 24 months in our hospital. We did not include children with NEC. We retrospectively analyzed clinical data and US examinations as regards the suspected causes and final diagnoses. Only 1 patient with HPVG required an immediate surgical intervention. This was - a 4-month-old girl 32 days after a repair of a congenital diaphragmatic hernia, with ultrasound signs of acute bowel wall necrosis. During surgery a bowel strangulation was revealed. Other causes included: - 4 patients with bowel inflammation (including complications of neoplastic diseases such as leukemia and Hodgkins'disease); - 3 patients with food allergy; - 1 patient with acute gastroenteritis; - 1 patient with hepatic injury because of a suspected metabolic disease; - 1 incidental finding revealed before closing a ventricular septum defect; - 1 patient during follow-up performed 2 weeks after a reconstruction of bowel continuity. CONCLUSIONS: HPVG is not always a sign of a life-threatening condition and it should not be by itself an indication for surgical treatment. HPVG requires a close monitoring of the clinical status, which is crucial for further management. In patients in non-severe clinical condition, we propose to perform a follow-up ultrasound imaging within 1-2 days, and not to extend diagnostic procedures, especially in case of ultrasound picture normalization. An abdominal ultrasound examination appears to be the method of choice for the identification of gas in the hepatic portal system in children.