High dose chemotherapy with consecutive autologous peripheral blood stem cell transplantation becomes increasingly important for the treatment of hematological diseases and solid tumors. A complete remission or at least a prolonged survival can be achieved for numerous malignant diseases by an intensification of chemo- and radiotherapy. Therefore, the autologous peripheral blood stem cell transplantation (PBSCT) represents an elementary precaution to reduce the therapy-associated aplasia by administration of hematopoietic precursor cells. Both, high dose chemotherapy with consecutive PBSCT demands great clinical experience and the collection, processing and positive selection of blood stem cells is a challenge for the Transfusion Medicine. Correct handling and utilization of blood stem cells for clinical and laboratory purposes (e.g. positive selection) must be guaranteed, since each restriction of the function of processed blood stem cells may lead to an insufficient engraftment after PBSCT. Therefore, the clinical divisions of the University Hospital Münster are planning and practising peripheral blood stem cell transplantations in cooperation with the Department of Transfusion Medicine. The collection, processing and quality control are performed by the Department of Transfusion Medicine in close contact with the other clinical departments, who subsequently perform high dose chemotherapy and peripheral blood stem cell transplantations.