Reports on 102 patients suffering from IgD-myeloma are reviewed and analyzed. Patients with IgD-myeloma are younger than patients with myeloma producing IgG or IgA myeloma proteins. Males are affected by this disease 3 times as often as females and 11 times as often as female patients in the group producing kappa light chain type of IgD myeloma protein. Hyperproteinaemia and extreme spikes of the monoclonal immunoglobulin occur less often. Approximately 90% of the patients have a lambda light chain myeloma protein and almost all patients excrete Bence-Jones protein. Renal insufficiency, amyloidosis, and plasma-cell leukemia are found more frequently than in other types of multiple myeloma. IgD-multiple myeloma carries a poorer prognosis, possibly related to the frequent finding of renal insufficiency.