This report details the evolution of bone marrow transplantation in Europe over a 20-year period. In 1973, 8 teams undertook a total of 16 allogeneic bone marrow transplants; in 1983, 97 teams performed 1353 transplants. In 1993, the numbers had risen to 260 teams and 7737 transplants. Donor source in 3092 cases was an allogeneic donor (2464 HLA-identical sibling transplants, 147 non-identical family donor transplants, 25 twin donor transplants and 456 unrelated donor transplants). For 4645 patients the transplant was autologous (2450 autologous bone marrow transplants, 1830 autologous peripheral blood stem cell transplants and 365 combined autologous peripheral blood and bone marrow transplants). Indications for transplants in 1993 were leukemias in 3419 patients (44%; 2332 allogeneic, 1087 autologous), lymphoproliferative disorders in 2666 patients (34%; 197 allogeneic, 2469 autologous), solid tumors in 1077 patients (14%; 9 allogeneic, 1068 autologous), aplastic anemia in 251 patients (3%; 250 allogeneic, 1 autologous), inborn errors in 244 patients (3%; 242 allogeneic, 2 autologous) and miscellaneous disorders in 80 patients (1%; 62 allogeneic, 18 autologous). These data illustrate the increase of hematopoietic stem cell transplants as a therapeutic modality over the last 20 years in Europe.