The optimal source of stem cells is a controversial issue in the field of autologous stem cell transplantation. A comparison of autologous bone marrow transplantation (BMT) and peripheral blood stem cell transplantation (PBSCT) after first remission induction treatment in multiple myeloma was made by a retrospective analysis of 132 transplants performed in 18 French Centers from 1984 to 1991 (81 autologous BMT, 51 PBSCT). The two groups differed in the median age (PBSCT 49 years; autologous BMT 55 years, P < 0.001), the duration of chemotherapy prior to transplantation, the interval between stem cell collection and transplantation, and in the conditioning regimen (more total body irradiation and higher doses of irradiation in the PBSCT group). The median time to neutrophil recovery was shorter in the PBSCT group (13 days vs. 20 days, P < 0.001), but the median time to platelet recovery did not differ significantly between PBSCT (26 days) and autologous BMT (22 days). There was no significant difference between the two groups regarding overall response rate (PBSCT 84%, autologous BMT 82%) and complete remission rate (PBSCT 37%, autologous BMT 36%). The actuarial relapse-free survival, time to treatment failure and overall survival were not significantly different. A case controlled study comparing 43 autologous BMT and 43 PBSCT matched for age and status at the time of transplantation did not show any advantage of PBSCT over autologous BMT in terms of immediate outcome, relapse-free survival, overall survival and time to treatment failure. Thus, in this retrospective analysis, the only significant benefit for PBSCT was reduced time to neutrophil recovery.