In this treatment, blood-forming cells are removed from the patient's or a donor's bone marrow, using a special instrument filtered from the bloodstream. These blood- forming cells called stem cells are preserved by freezing while the patient receives high-dose chemotherapy. One complication of high-dose chemotherapy is destruction of the patient's bone marrow stem cells. Although this complication would otherwise be fatal, it can be avoided by transplanting the frozen stem cells to the patient after chemotherapy. This allows doctors to use extra high doses of chemotherapy that might increase the likelihood of curing multiple myeloma.

Autologous transplants which use the patient's own bone marrow or peripheral blood stem cells are fairly safe and have a low risk of serious complications. Unfortunately, because it is difficult to completely kill all the myeloma cells with the high dose chemotherapy, most patients who undergo this procedure will eventually have their myeloma return. Although a small number of these patients will be free of their myeloma for quite a long time, it is not possible to say that this procedure is curative.

Allogeneic transplants use stem cells from donors (usually close relatives or, less often, unrelated donors whose tissue type is closely matched to the patient). Allogeneic transplants carry a higher risk of serious complications, even death, but may produce more long lasting remissions because the transplanted (donor) immune system cells may actually help to destroy the myeloma cells. This procedure is not used often in myeloma patients because the patients must be relatively young and healthy in order to withstand the side effects of transplantation (most myeloma patients are elderly), and there must be a donor whose tissue type is compatible with the patient's.