Bone marrow transplantation (BMT) has evolved from an experimental undertaking to an established therapeutic strategy for hematological neoplasias, severe aplastic anemia, congenital immunological and metabolic disorders and some solid tumors. This report summarizes the main indications for autologous and allogenic transplants, the prerequisites and potential techniques, early and late complications as well as preventive and therapeutic strategies. The results of 397 BMT, 357 allogeneic and 40 autologous transplants, performed in Basel between 1973 and 1995, illustrate the present potential and main prognostic factors: stage of disease, age and histocompatibility. 50% of the patients treated with an allogeneic BMT from an HLA-identical sibling early in the disease are alive 15 years post BMT, 80% free of disease and reintegrated into work and family. New strategies are testing the use of unrelated HLA-compatible volunteer donors and the potential of mobilized peripheral blood precursor cells instead of bone marrow for allogeneic and autologous transplants.