We describe an infant with multiple segmental areas of atresia of the small and large bowel, with histologic features characteristic of the hereditary form of the disease. Posttransfusion graft-versus-host disease developed first, and then immunodeficiency was found. This report confirms the association between hereditary multiple intestinal atresia and immunodeficiency. We recommend irradiation of blood products in patients with multiple intestinal atresia pending evaluation of immune system status.