Between January 1, 1972 and December 31, 1985, 28 cases of IgD myeloma were diagnosed in the Languedoc region, southern France. These cases did not show the male predominance and early development usually found with this type of myeloma. Comparisons with a series of myelomas of all types detected in the same region during a similar period revealed an increased frequency of extramedullary clinical localizations, osteolytic lesions, anaemia and renal impairment. The monoclonal component was sometimes meagre, but it could be detected by electrophoresis on cellogel in 81 per cent of the cases. The lambda isotype, largely predominant, might account for these biological abnormalities and for a particularly sombre prognosis: the median survival was 11 months as against 29 months with myelomas of all types. There was no statistically significant correlation between any of the clinical and laboratory findings and the duration of survival.