Intra-aortic balloon occlusion (IABO) of the thoracic aorta was attempted in 21 consecutive hemodynamically unstable patients with missile injuries of the abdomen. Retrospectively, the patients fell into three groups. Group One consisted of five patients with a cardiac rhythm but no recordable blood pressure (BP). Group Two were six patients with refractory hypotension, that is, BP of 80 torr systolic or less. Group Three comprised ten patients who had hemodynamic deterioration to a BP of 80 torr systolic or less during preparation for or in the course of celiotomy. IABO was successful in occluding the thoracic aorta in 20 patients with a resultant rise of BP; one patient required thoracotomy for aortic clamping. Operative control of hemorrhage was accomplished in 11 patients; seven patients survived and were discharged in a functional status. There were no survivors in Group One, three in Group Two, and four in Group Three.