Autoperfusion Balloon Catheters (APBC) were inserted into the renal arteries of seven dogs for about two and a half hours. Abdominal aortography showed renal arterial flow of the kidney obstructed by APBC. Macroscopic and microscopic examination revealed no significant changes in the resected specimen. It is concluded that APBC is useful in cases of proximal arterial occlusion by maintaining the blood supply to the distal organs for relatively short periods and that it can be used for the treatment of rupture of arteries which feed critical organs.