Two IgA-deficient children with inflammatory myopathy and intestinal malabsorption were evaluated. The myopathy was characterized by weakness of facial and proximal limb muscles, increased serum concentrations of lactic dehydrogenase and creatine phosphokinase, and histologic evidence of inflammation and degeneration of muscle fibers. Features of the intestinal abnormality were blunted villi, interstitial inflammation, and reduction in IgA-containing plasma cells and IgA content of epithelial cells. The myopathy and malabsorption improved with corticosteroid treatment. Circulating antibodies to striated muscle could not be demonstrated in either patient, but one had antibodies to milk and chicken serum proteins. We speculate that IgA deficiency may predispose to the development of inflammatory myopathy.