Ninety-one congenitally immunodeficient patients treated from 1972 to 1981 were reviewed to assess the incidence and nature of gastrointestinal complications. Thirty-three of these patients (36%) developed 59 complications. Patients with immunodeficiencies characterized by neutrophil dysfunction - chronic granulomatous disease (20 patients) and cyclic neutropenia (eight patients) - developed 22 surgical infections, 22 of which required operation. In patients with neutrophil defects, postoperative morbidity was frequent and severe. Gastrointestinal symptoms were common in patients with isolated defects of B or T lymphocytes. Ten of forty-one patients with congenital hypogammaglobulinemia developed gastrointestinal complications, as did one of four patients with DiGeorge syndrome, and the single patient with secretory IgA deficiency. However, operation was not required for these patients with isolated disorders of lymphocyte function. Patients with combined B and T cell disorders developed gastrointestinal disease, requiring operative therapy at intermediate rates. Gastrointestinal symptoms developed in four of nine patients with severe combined immunodeficiency and three of eight with Wiskott-Aldrich syndrome. Operative therapy was required in two of these seven symptomatic patients.