Upper gastrointestinal bleeding secondary to ulcer disease is common and results in substantial patient morbidity and medical expense. After initial resuscitation to stabilize the patient, carefully performed endoscopy provides an accurate diagnosis and identifies high-risk ulcer patients who are likely to rebleed with medical therapy alone and will benefit most from endoscopic hemostasis. For patients with major stigmata of ulcer hemorrhage--active arterial bleeding, nonbleeding visible vessel, and adherent clot--combination therapy with epinephrine injection and either thermal coagulation (multipolar or heater probe) or endoclips is recommended. High-dose intravenous proton pump inhibitors are recommended as concomitant therapy after successful endoscopic hemostasis. Patients with minor stigmata or clean-based ulcers will not benefit from endoscopic treatment and should receive high-dose oral proton pump inhibitor therapy. Effective medical and endoscopic management of ulcer hemorrhage can significantly improve outcomes and decrease the cost of medical care by reducing rebleeding, transfusion requirements, and the need for surgery.