Aim: Philadelphia-negative chronic myeloproliferative neoplasms (Ph-negative MPNs) are associated with various genetic abnormalities. The JAK2 V617F mutation is the most common one and plays a crucial role in diagnosis. We aimed to evaluate the relationship between JAK2 mutational burden and clinical parameters of MPN patients. Methods: The present cross-sectional study was conducted on patients with MPN referred to our clinic for JAK2 mutation screening between January 2019 and December 2020. The clinical information of the patients was obtained from the hospital automation system and records in the hematology and medical genetics departments. We evaluated 143 JAK2 positive patients diagnosed with polycythemia vera, primary myelofibrosis (PMF) and essential thrombocythemia. Results: The mean age of the patients was 60.29 (standard deviation:14.81). The mutational burden was correlated with spleen size and lactate dehydrogenase (LDH) level, particularly in PMF (p=0.002, p=0.003, respectively). There was no significant difference in age, gender, mutation burden and laboratory findings in patients with and without thrombosis and bleeding. Conclusion: Clinical parameters and JAK2 mutational burden are related, but this relationship differs based on the MPN types. The spleen size in MPN, particularly massive splenomegaly and high LDH levels, may be correlated with the JAK2 mutational burden. This relationship is more pronounced for PMF. There is no significant relationship between JAK2 mutational burden and vascular complications such as thrombosis and bleeding.