To determine the effectiveness of angiography in identifying bleeding sites and controlling the massive and often fatal hemorrhage accompanying pelvic fractures, the hospital course and outcome of 28 patients who underwent angiography after pelvic trauma were reviewed. In 20 patients, active bleeding was demonstrated. Transcatheter occlusions of bleeding arteries were performed in 18 of these, with angiographic ontrol of hemorrhage in 18 and clinical control in 17. Two patients with active bleeding were not embolized because of subsequent surgical intervention in one and technical angiographic difficulties in the other. Blood transfusion requirements averaged 32.1 units in the 48 hr or less before occlusion and 5.2 units during 48 hr after occlusion. Of the 18 patients who underwent arterial embolization, nine died, seven of associated injuries, one of extrapelvic hemorrhage, and one of hypotension. Nine patients survived to be discharged. These results confirm that transcatheter occlusion of bleeding vessels in the pelvis reduces hemorrhage and facilitates the management of patients with pelvic trauma.