Objectives: Arterial and venous thrombotic events are more commonly observed in patients with myeloproliferativediseases (MPDs). Arterial and venous thromboses are significant causes of mortality and morbidity in Philadelphia (Ph)chromosome-negative MPDs. The present study investigates the presence of the JAK2V617F mutation, which contributes to the early diagnosis of MPD, in patients with ischemic heart disease with a normal coronary angiography and inthose with a venous thrombosis in an atypical location. The goal in this regard is to determine the contribution of theJAK2V617F mutation to the development of thrombosis in Philadelphia chromosome-negative MPDs, and to identifypossible relationships between the JAK2 mutation and other clinical and laboratory characteristics.Methods: The study was conducted in the Division of Hematology of the Department of Internal Medicine in theTrakya University Faculty of Medicine between March 2008 and August 2009. Approval for the study was granted by theEthics Committee of the Trakya University Faculty of Medicine on February 21, 2008, and the study was supported bythe Trakya University Scientific Research Projects Fund. A total of 87 subjects were included in the study. The JAK2V617Fmutation was analyzed using a real-time PCR device and with a melting curve analysis. The demographic and medicaldata of the patients was retrieved from the medical charts. The statistical analysis was performed using SPSS 13.0 dataanalysis software.Results: The study included 31 patients diagnosed with myeloproliferative disease, 32 patients with ischemic heartdisease with a normal coronary angiography and four patients with a venous thrombosis in an atypical location, as wellas 20 healthy volunteers included in the control group. The JAK2V617F mutation was identified in 24 patients (77.4%)with myeloproliferative disease, in one patient (3.1%) with cardiovascular disease and in two patients (50%) with avenous thromboembolism in an atypical location. No JAK2V617F mutation was found in the healthy control group.There was no difference between myeloproliferative disease subgroups in terms of history of thrombosis. No significantrelationship was found between the presence of the JAK2V617F mutation, history of thrombosis and leukocyte count,or between leukocyte count and history of thrombosis (p=0.183, p=0.345, p=0.368, respectively).Conclusion: The identification of the JAK2V617F mutation in three patients with thrombosis with no diagnosis of myeloproliferative disease suggests that the detection of this mutation in patients with a venous thromboembolism in anatypical location and in some patients with an arterial thrombosis may contribute to the early recognition of patients withmyeloproliferative disease, and may give these patients the chance to begin the appropriate therapy. The rate of a historyof thrombosis was higher in the JAK2V617F-positive patients, although the difference did not reach statistical significance