The association of pernicious anemia, an autoimmune disease, with other immunologic disorders such as dermatitis herpetiformis, Hashimoto's thyroiditis, hypothyroidism, hyperthyroidism, vitiligo, adrenal insufficiency, adult-onset immunoglobulin deficiency, hypoparathyroidism, and possibly diabetes mellitus has been reported. The association of pernicious anemia with giant cell myocarditis, a rare fatal illness believed by some to represent an autoimmune abnormality occurring with other autoimmune diseases such as thymoma, systemic lupus erythematosus, dermatomyositis, thyrotoxicosis, Wegener's granulomatosis, and Sjogren's syndrome, is reported for the first time. A common underlying autoimmune abnormality is suggested.