Analysis of prognostic factors has been made in 369 allogeneic transplants for multiple myeloma reported to the registry of the European Group for Blood and Bone Marrow Transplantation (EBMT). Favorable prognostic factors for obtaining a complete remission (CR) were stage I at diagnosis (CR 77%), one line of treatment before conditioning (CR 52%), CR before conditioning (CR 60%), and Ig A or light chain myeloma (CR 43% and 42%). Factors that predicted significantly for favorable survival in a univariate analysis included having received only one line of treatment, female sex, stage I at diagnosis, stage I at conditioning and a beta 2-Microglobulin less than 4 mg/l. Favorable post-BMT factors consisted of obtaining a CR following BMT and not being in graft-versus-host disease stage III or IV. A multivariate analysis of pre-BMT factors showed that the sex of the patient and the number of lines of treatment pretransplant were independent prognostic factors. Allogeneic BMT is a promising treatment method for patients who have received only one line of treatment, particularly if they are of the female sex. BMT late in the course of the disease is usually unsuccessful.