The Authors describe a case of congenital coagulation factor V deficiency with severe prenatal intraventricular hemorrhage. Factor V is an essential enzyme catalysing the process of thrombin generation. Low levels of enzyme were also found in both parents, who demonstrate subclinic alterations of coagulation parameters. The severe deficiency of factor V in the newborn (8%) caused frequent and severe intracranial and gastric hemorrhages that brought newborn to death in few weeks.