Gastrointestinal hemorrhage requiring admission to the intensive care unit is uncommon. An understanding of the etiologies of upper and lower gastrointestinal bleeding, many of which have a specific predilection to occur at certain ages, is crucial in using diagnostic techniques efficiently. The management of gastrointestinal hemorrhage should begin with a rapid but thorough assessment of the child's hemodynamic stability and amount of blood loss. Restoration of hemodynamic stability with volume expansion and appropriate use of blood products is the initial goal of therapy followed by measures to specifically localize and manage the bleeding. A multidisciplinary team approach including gastroenterologists and surgeons is essential in the treatment of these children. Endoscopy of both the upper and lower gastrointestinal tract are useful diagnostic and potentially therapeutic tools that should be performed in select cases after hemodynamic stability has been achieved. Critically ill children often have risk factors that make them prone to developing stress ulcers which can cause significant bleeding, and high-risk groups will benefit from acid-suppressive therapy with histamine receptor antagonists and/or proton pump inhibitors.