Myeloproliferative disorders are caused by abnormalities of hematopoietic stem cells leading to uncontrolled proliferation of one or more cell lines in the blood. Besides sharing common clinical and hematologic features they are characterized by clonal hematopoiesis and genetic instability, resulting in a disease-specific rate of transformation into acute leukemia. This review discusses relevant clinical and prognostic aspects as well as current diagnostic and therapeutic procedures of polycythemia vera, essential thrombocythemia and chronic idiopathic myelofibrosis.