A patient with cutaneous anergy and miliary tuberculosis was studied with serial determinations in vivo of skin test responsiveness to natural antigens and to vesicant doses of dinitrochlorbenzene, and in vitro with buffy coat migration inhibition, indirect migration inhibition factor production, and lymphocyte transformation during the acute phase of the disease and during convalescence. During the anergic phase, the patient maintained good lymphocyte transformation to phytohemagglutinin and purified protein derivative of tuberculin and showed strong buffy coat migration inhibition that was partially dependent on autologous serum but not complement; however, indirect migration inhibition factor production to purified protein derivative was not demonstrable. the results suggest that the defect in anergic tuberculosis resides at least partially in the nonimmunologic inflammatory response and that lymphocyte function is at least partially intact.