Blood stem cell transplantation has become an established therapeutic option in the treatment of malignant diseases. At the same time molecular therapeutic approaches (i.e. gene therapy) are promising alternatives to the classical treatment of cancer. The proceedings give an overview of the biology of hematopoietic progenitor cells, peripheral stem cell transplantation in patients with hematological malignancies, recent developments in molecular diagnosis and gene therapeutic concepts, and show that successful future developments require cooperative research connecting basic science with clinical application.