The usefulness of arteriography and transcatheter treatment was studied in nine patients with gastrointestinal hemorrhage and acquired immunodeficiency syndrome (AIDS). Selective arteriography was performed in all patients; transcatheter treatment was performed by means of embolotherapy or selective vasopressin infusion. Medical records were reviewed to determine the cause of hemorrhage and clinical outcome. Arteriography enabled identification of the site of hemorrhage in seven patients. Hemorrhage was caused by Kaposi sarcoma (n = 2), cytomegalovirus colitis (n = 1), lymphoma (n = 2), or unknown causes (n = 4). Neovascularity and dense parenchymal stain were present in patients with Kaposi sarcoma. Transcatheter treatment consisted of embolization (n = 3), vasopressin infusion (n = 2), or both (n = 1). Hemorrhage was controlled in six cases in which transcatheter treatment was administered. Complications included thrombosis of the femoral artery in a 7-month-old infant and formation of a pseudoaneurysm of the femoral artery, which was treated successfully with ultrasound-guided compression. In patients with AIDS and profuse gastrointestinal hemorrhage, arteriography often enables identification of a specific site of hemorrhage, which can be stopped with transcatheter treatment.