A retrospective review of 409 patients with bile duct obstruction (373 undergoing definitive surgery and 36 undergoing laparotomy only) identified 27 patients who developed significant postoperative gastrointestinal bleeding necessitating transfusion. All 27 had undergone a definitive procedure to relieve obstruction. Nineteen patients required blood replacement of six or more units. The majority of patients bled in the first four postoperative days. The sites of hemorrhage were identified in 25 patients, gastric erosions being the most common lesions detected. Thirteen of the 27 patients died, seven due to overwhelming blood loss despite massive transfusion. Eight of the 27 required an operation because of bleeding. An analysis of the relationship between preoperative factors and gastrointestinal bleeding identified three factors that were independently associated with this complication. These were: 1) an initial hematocrit of 30% or less; 2) an initial leukocyte count in excess of 10 X 10(9)/l; and 3) a malignant obstructing lesion. Patients with two or all three of these factors were identified as being at very high risk of developing postoperative gastrointestinal hemorrhage. Bleeding into the upper gastrointestinal tract has been confirmed to be a major problem in the surgical management of patients with obstructive jaundice. Further studies of the etiology and prevention of this complication are indicated.