In most cases, acute diarrhea in childhood heals spontaneously, but it may become the form of chronic diarrhea in immunodeficient children and then cause weight loss, dehydration, malabsorption and malnutrition. The immunodeficient diseases associated with chronic diarrhea include severe combined immunodeficiency syndrome, common variable immunodeficiency, acquired immunodeficiency syndrome, agammaglobulinemia or selective IgA deficiency. IgA deficiency is the most common primary immunodeficiency. Because many IgA deficient individuals seem to have compensated for their deficiency with increased IgM production and various nonimmunologic factors, the incidence of gastrointestinal involvement is not prominent. Some of those with IgA deficiency and recurrent infections have been found to also have IgG subclass deficiency. IgA deficiency with IgG₂ and IgG₄ subclass deficiency have high susceptability to infection and chronic diarrhea. IgG subclass deficiency, when present, is more likely to be found in association with a partial IgA deficiency rather than complete IgA deficiency. We report a 3-month-old male with intractable diarrhea accompanied by IgA, IgG₂, and IgG₄ deficiency.