Approximately 40 to 50 infants and children with similar epidemiologic, clinical, and laboratory features of AIDS have been described. The occurrence of significant numbers of patients with PAIDS in geographic areas that are associated with similar risk factors and clinical features of AIDS suggests a common cause. Immunologic evaluation reveals hypergammaglobulinemia, decreased or absent antibody responses after immunization, normal to decreased T-cell numbers, decreased helper/suppressor cell ratios, and abnormal results of functional studies of T-cells. None of the patients described has the clinical or laboratory features of well-established congenital immunodeficiency disorders. No consistent viral agent has been documented except for antibody to ARV and HTLV III. The frequent finding of T-cell abnormalities in the mothers of infants with PAIDS is in contrast to the absence of such abnormalities in the mothers of infants with congenital immunodeficiency disorders. Future studies in PAIDS should be directed toward uncovering the etiology and risk factors as well as determining the response to treatment with various methods of immunologic reconstitution.