Vitamin K prophylaxis for all neonates has been recommended to prevent hemorrhagic disease of the newborn (HDN), but it is still an uncommon practice in most developing countries throughout the world. In the United States and Canada, where vitamin K injections continue to be recommended in the newborn period, HDN is not a major concern. The risk factors for HDN include inadequate vitamin K prophylaxis, exclusively breast-fed infants, diarrhea, and alternative causes of vitamin K deficiency, such as liver disease and cystic fibrosis. We present an exclusively breast-fed 3-week-old infant with diarrhea for 2 days who died from intracranial hemorrhage related to HDN despite having received a single intramuscular injection of 0.2 mg of vitamin K at birth. Hemorrhage in the infant from vitamin K deficiency should be a concern for pediatricians and obstetricians. We emphasize the importance of administering an adequate dosage of vitamin K for prevention of HDN, particularly in an exclusively breast-fed infant.