Deficiency of vitamin K predisposes to early, classic or late hemorrhagic disease of the newborn (HDN); late HDN may be associated with serious and life-threatening intracranial hemorrhage. Late HDN is characterized by intracranial bleeding in infants aged 1 week to 6 months due to severe vitamin K deficiency, occurring particularly in exclusively breastfed infants. Late HDN is still an important cause of mortality and morbidity in developing countries where vitamin K prophylaxis is not routinely practiced. In this study, we report on two siblings with intracranial bleeding who were fully breastfed without a routine supplementation of vitamin K. Vitamin K should be given to all newborns as a single, intramuscular dose of 1 mg.