To assess course and outcome of patients with endoscopically diagnosed Mallory-Weiss tear bleeding. Thirty-four subjects seen during a 5-yr period formed the study group. Available follow-up after index bleed was 27.5 months +/- 2.7 SEM. There was no antecedent explanation for the tear, such as nausea, retching, abdominal pain, or vomiting in 12/28 (42.9%). Hematemesis on first emesis was noted in 13/26 (50%). Mean transfusion requirements were 2.6 +/- 1.0 (SEM) units of packed cells (range, 0-28), and 9/34 (26.5%) received four or more units. Two had therapeutic endoscopy and three required surgery to control bleeding. Thirty-day mortality noted four deaths, all multiorgan system failure related to the bleed. Patients who died had other endoscopic abnormalities, such as ulcers or varices, and all had an alcohol history. Two patients of 20 contacted had recurrent bleeding. One had another tear. The other had intermittent recurrent bleeding and refused care. Mallory-Weiss tear bleeding may be significant and recurrent. It may cause death or require transfusion, therapeutic endoscopy, and surgery.