The present report summarizes the main clinical and immunochemical features of 17 patients with IgD myeloma and compares than with the evidence reported in the literature. The difficulties inherent in the immunodiagnosis of this disease, particularly in detection of the M-component, typing of IgD and demonstrating its monoclonal nature, are discussed on the basis of personal observations and those of other investigations. Special emphasis is placed on clinical and immunochemical characteristics of IgD kappa myeloma. Immunoquantitation of serum IgD is considered to be the most reliable method of immunodiagnosis.