Objective: Myeloproliferative neoplasms (MPNs) share common clonal stem cells but show significant differences in their clinical courses. The aim of this retrospective study was to evaluate thrombotic and hemorrhagic complications, JAK2 status, gastrointestinal and cardiac changes, treatment modalities, and survival in MPNs in Turkish patients. Materials and Methods: Medical files of 294 patients [112 essential thrombocythemia (ET), 117 polycythemia vera (PV), 46 primary myelofibrosis, and 19 unclassified MPN cases] from 2 different universities in Turkey were examined. Results: Older age, higher leukocyte count at diagnosis, and JAK2 mutation positivity were risk factors for thrombosis. Platelet count over 1000x109/L was a risk factor for hemorrhagic episodes. Hydroxyurea treatment was not related to leukemic transformation. Median follow-up time was 50 months (quartiles: 22.2-81.75) in these patients. Patients with primary myelofibrosis had the shortest survival of 137 months when compared with 179 months for ET and 231 months for PV. Leukemic transformation, thromboembolic events, age over 60 years, and anemia were found to be the factors affecting survival. Conclusion: Thromboembolic complications are the most important preventable risk factors for morbidity and mortality in MPNs. Drug management in MPNs is done according to hemoglobin and platelet counts. Based on the current study population our results support the idea that leukocytosis and JAK2 positivity are more important risk factors for thrombosis than hemoglobin and platelet values.