OTCD can present with ALF at any age. Under adequate therapy symptoms resolve quickly. We report a three-yr-old girl with the manifestation of an OTCD as ALF. Despite adequate pharmacotherapy and protein restriction, the patient deteriorated and developed hepatic encephalopathy. A high urgency liver transplantation was performed and the patient recovered completely. We conclude that in patients with ALF urea cycle defects in general and OTCD in particular should be considered as differential diagnosis. Patients should be managed in a center that has the capacity for an emergency liver transplantation.