In spite of extensive precausions and antibiotic therapy, pylephlebitis was found in 11 of 200 dead newborns as complicat infection after umbilical vein catherization. All stages from local pylephlebitis to suppurative hepatitis were found. The clinical manifestations are not characteristic and therefore misinterpreted very often. Umbilical vein infection should be taken into account in every newborn child with or after umbilical vein catheterization, even when the umbilicus appears normal, when body temperature is rising, the general condition is turning to the worse, and icterus is increasing. Blood picture and transaminase values might be helpful parameters. Reviewing the literature and reporting a case of fatal portal hypertension, pylephlebitis after umbilical vein catheterization is shown as a possible cause of the pseudo-Banti-syndrome in children.