Purpose: Use of umbilical catheters is standard practice in neonatal intensive care units due to ease of insertion and provision of longer-term vascular access. Complications of umbilical venous catheters, including extravasation of total parenteral nutrition (TPN) fluid, are rare but when they occur have high mortality and morbidity. Umbilical venous catheters tend to migrate over time, and their position may change, so a high index of suspicion should be maintained. Our aim was to describe a case with extravasation of parenteral nutrition fluid and review the medical literature. Patients and Methods: Case report. Results: The infant was born at 28 weeks' gestation (1510 g). On day 6 he presented with nonspecific abdominal distension, hypotension, respiratory deterioration, metabolic acidosis and was critically ill. Radiological and ultrasound findings were consistent with TPN ascites due to a malpositioned umbilical venous catheter. Bedside paracentesis without laparotomy was carried out. Despite a stormy course, the infant recovered and the liver injury with conjugated hyperbilirubinemia improved over a period of several months. Conclusion: Emergency bedside ultrasound and paracentesis with catheter removal may be lifesaving and avoid laparotomy in an already critically unwell preterm infant.