Advances in molecular biology and genomics enabled more detailed view on the pathogenesis of myeloproliferative disorders, which are considered to be a diseases of hematopoietic stem cell. The autor provides an brief overview of the genetic alterations, leading to the chronic myeloid leukemia, myelodysplastic syndrome and acute myeloid leukemia. In the second part, molecular targeted therapies that have been developed based on these insights are reviewed. These are particularly methods preventing increased proliferation such as inhibition of tyrosinkinases (imatinib, dasatinib), inhibitions of farnesyltransferase (tipifarnib), inhibition of angiogenesis (bevacizumab, vatalanib), induction of diferentiation (hypomethylating agenents) and induction of apoptosis (bortezomib). More detailed information is given on some novel drugs which are currently in clinical trials.