Bare lymphocyte syndrome (BLS) is a rare disorder characterized by deficient expression of human leukocyte antigens (HLA antigens) and combined immunodeficiency to various degrees. Recurrent severe infections especially due to opportunistic organisms are common. Here, we present two patients with BLS who lack both class I and II antigens (Type III). They had the typical clinical and immunologic findings of BLS. The first patient showed marked improvement in pulmonary symptoms resulting from cytomegalovirus infection by means of gancyclovir treatment. However, intramuscular injections of interferon-alpha (IFN-alpha) had no beneficial effect in either the expression of HLA antigens or the clinical status. The second patient died of septicemia while being prepared for bone marrow transplantation.