Two-hundred and 31 patients with a newly diagnosed multiple myeloma first seen and admitted to 17 hospitals located in the North-East of Italy between 1987 and 1992, were registered for a prospective study on the course of the disease. Median age was 68 years (range 41-90). Fifty-one per cent were in stage I, 9% in stage II and 40% in stage III. The presenting features and the survival of the 61 (26%) patients who were first admitted to a division of Hematology of a University Hospital (group HEM) were compared with those of the 170 (74%) patients who were referred to 16 divisions of Internal Medicine at General and County Hospitals (group INT). In the latter group, the patients were older (p = 0.002), had a poorer performance status ( p = 0.0001 ), a higher frequency of renal failure (p = 0.006) and anemia (p = 0.02) and higher beta2 microglobulin levels (p = 0.01). Median survival of group HEM patients did not differ significantly from group INT patients, if all stages were considered, but stage II and III patients of group INT had a significantly shorter median survival than advanced stage patients of group HEM (12 vs. 35 months, p = 0.01). If those older than 65 years or with unfavourable prognostic factors at presentation were excluded, prolonged survival of group INT patients was observed and the curves of the two groups did not differ significantly anymore. These results show that the patients recruited by a specialized centre may represent a selected population with better prognostic factors and younger age and this may affect analysis of clinical trials. Participation of minor centres in clinical trials may considerably contribute in improving interpretation of results of therapy in myeloma and be more representative of the entire population.