The Nordic Myeloma Study Group conducted an open randomized trial to compare bortezomib as consolidation therapy given after high-dose therapy and autologous stem cell transplantation (ASCT) with no consolidation in bortezomib-naive patients with newly diagnosed multiple myeloma. Overall, 370 patients were centrally randomly assigned 3 months after ASCT to receive 20 doses of bortezomib given during 21 weeks or no consolidation. The hypothesis was that consolidation therapy would prolong progression-free survival (PFS). The PFS after randomization was 27 months for the bortezomib group compared with 20 months for the control group (P = .05). Fifty-one of 90 patients in the treatment group compared with 32 of 90 controls improved their response after randomization (P = .007). No difference in overall survival was seen. Fatigue was reported more commonly by the bortezomib-treated patients in self-reported quality-of-life (QOL) questionnaires, whereas no other major differences in QOL were recorded between the groups. Consolidation therapy seemed to be beneficial for patients not achieving at least a very good partial response (VGPR) but not for patients in the >= VGPR category at randomization. Consolidation with bortezomib after ASCT in bortezomib-naive patients improves PFS without interfering with QOL. This trial was registered at www.clinicaltrials.gov as #NCT00417911.