Background and Objectives: The association of JAK2 V617F mutation with myeloproliferative neoplasms was first reported in 2005. The present study was conducted to evaluate the frequency of JAK2 gene mutation in patients with myeloproliferative neoplasms in Kerman, Iran, from the years 2013 to 2018. Materials and Methods: This descriptive cross-sectional study was performed among 276 patients with primary diagnosis of myeloproliferative neoplasms with subgroups PV, ET, PMF, and ABL-BCR negative referring to bone marrow laboratory of Bahonar Hospital during six years. Demographic, histopathologic, clinical, and JAK2 mutation data were collected. Data were analyzed by K2 test, Mann-Whitney U test and Kolmogorov– Smirnov test. Results: Out of the total number of participants, 176 (64. 9%) were male and 100 (35. 1%) female with 101 (36. 6%) patients having primary thrombocythemia, 81 (29. 3%) primary myelofibrosis, 72 (26. 1%) polycythemia vera, and 22 (8%) without diagnosis. Of all patients, JAK2 mutation was positive in 184 patients (66. 6%). But the results showed that the frequency of positive mutations was 54. 4% in primary thrombocytic patients, 59. 2% in primary myelofibrosis patients, and 88. 7% in polycythemia patients. This difference was statistically significant. ( p = 0. 016) Conclusions: Considering the comparability of JAK2 V617F mutation rate in Iranian patients with myeloproliferative neoplasms and previous reports, in order to standardize the diagnosis and control of treatment and prognosis, it seems neccessary to evaluate this mutation along with other histopathologic evaluations.