The clinical and immunologic features of two adolescent boys who had recurrent pyogenic infections are judged to constitute a new syndrome. Its characteristics include: recurrent cutaneous, pulmonary, and joint abscesses; growth retardation; coarse facies; chronic dermatitis; exquisite immediate hypersensitivity associated with exceptionally high serum concentrations of IgE and eosinophilia; and depressed in vivo cellular immunity and antibody formation. These patients lacked evidence of respiratory allergy or parasitism. Atopic dermatitis was not present in one boy and the physical characteristics of the other boy's dermatitis were not typical for that entity. Concentrations of immumnoglobulins G, A, M, D and the various IgG subtypes were normal, as were natural antibody titers to red cell antigens. Nevertheless, depressed anamnestic antibody responses were noted to diphtheria and tetanus antigens and neither patient demonstrated responses to primary immunization with KLH, typhoid, and DNCB antigens. Complement and polymorphonuclear functions were normal. In vitro lymphocyte studies done demonstrated normal DNA synthesis in phytohemagglutinin and staphylococcal antigen-stimulated cultures and MIF production by some antigen-stimulated cultures from each. The explanation for the undue susceptibility to infection, increased IgE production, subnormal antibody formation, and impaired in vivo cell-mediated immunity in these patients remains conjectural.