During last decades major changes have occurred in clinical practice of haematopoietic stem cell transplantation (HSCT), which has become a standard part of therapy for selected diseases. HSCT today includes grafting with allogeneic and autologous stem cells derived from bone marrow, peripheral blood or cord blood. Major limitations are availability of suitable matched donors, complications as graft-versus-host disease, slow recovery of immune function, infections and relapse of advanced malignant diseases. The results of allogeneic HSCT have improved as DNA typing to identify the most closely matched donors have been developed. With reduced intensity conditioning regimens is allogeneic HSCT available also for older patients. At present, HSCT provides the best chances for a cure for many malignant or nonmalignant diseases.