High-dose treatment (HDT) with autologous stem cell transplant (ASCT) is superior to conventional chemotherapy in multiple myeloma. However, relapses eventually occur, especially in the presence of unfavourable cytogenetic abnormalities, high beta-2 microglobulin levels prior to transplant and extensive prior treatment. Cytotoxic consolidation chemotherapy, following tandem transplants (TT), was given to 75 myeloma patients with at least one poor prognostic factor. When their outcome was compared with that of 75 matched controls who received dexamethasone +/- interferon post TT, no event-free or overall survival advantage was observed. Other approaches may be required to improve survival in multiple myeloma.