Inclusion Criteria:  Male and female patients with Primary Myelofibrosis (PMF), post-Polycythemia Vera-Myelofibrosis (PPV-MF), or post-Essential Thrombocythemia-Myelofibrosis (post-ET-MF), for whom Jakavi® therapy is indicated. Patients that were informed about all aspects of this NIS and provided written informed consent.  Exclusion Criteria:  -