The clinical and laboratory features of a child with chronic granulomatous disease (CGD) and IgA deficiency and his family are presented. Bactericidal and NBT dye reduction studies confirmed the diagnosis of CGD in the patient and the carrier state in the mother. No other family member had IgA deficiency. The manifestations of the IgA deficiency include multiple autoimmune antibodies, progressive pulmonary dysfunction but no gastrointestinal or rheumatoid symptoms. The etiology of the IgA deficiency appears to be a failure in terminal B cell differentiation as evidenced by the presence of normal numbers of IgA bearing cells detected by a fluorescent monospecific antisera, a normal profile of T cell subpopulations, normal responses to the mitogens PHA, Con A, PWM, and antigens C. albicans, E. coli, and S. aureus, and the absence of suppressor cell activity in co-culture assays. The significance of the association of these two disorders is discussed.