The relation between overall survival time (OS) and response level (CR, 75%R, PR, MR, SD) was analysed in 432 multiple myeloma patients from 4 prospective Finnish Leukaemia group trials, treated with conventional chemotherapy. The primary regimen was either melphalan and prednisolone or combination chemotherapy with melphalan as a main component. Both the influence of the pre-treatment factors in patients with different levels of responses and the aspects related to chemotherapy were analysed. The 324 patients aged up to 70 yr and the 10(8) older patients were dealt with as separate groups. Irrespective of the primary chemotherapy regimen, the level of response was not significantly influencing in the OS time, and this was true in both age categories. The median OS of the patients up to 70 yr of age who had any response was 57 months, compared to the 10 months of those with PD (p < 0.001). The corresponding figures for the older patients were 40 and 4 months (p <0.001), respectively. The pretreatment prognosticators for the patients with minimal responses were not more favourable than for patients with responses at higher levels. The prolonged primary chemotherapy was favourable in patients having responses less than PR. Accordingly, the primary goal of conventional chemotherapy for multiple myeloma is stabilization of disease, not the level of response.