The JAK-STAT is the most important pathway that transmits signals in the cells of normal hematopoiesis and hematologic malignancies. JAK2V617F, which develops in the JH2 region of the JAK2 kinase, is a somatic point mutation. As a result of JAK2V617F mutation, growth of the cells independent of cytokine commences which, in return, produces an increased response to cytokine and causes antiapoptotic effects. Some recent studies have reported that JAK2V617F mutation is seen in 1-10% of AML patients. Compared to those with de novo AML, JAK2V617F mutation is even higher in patients with AML, which develops secondary to myeloproliferative disorders. In this study the incidence of JAK2V617F mutation in AML patients was examined. The study includes 51 patients with AML. Fourteen percent had secondary AML, 86% had de novo AML. Twenty-four of the 51 patients were newly diagnosed to have AML and the rest 27 were studied in remission. Genetic analysis of JAK2V617F mutation was performed by using PCR. The results showed that none of our patients had JAK2V617F mutation. This might be attributed to the small number of patients in the study, which develops secondary to myeloproliferative disorders. Another reason could be that JAK2V617F mutation might have disappeared in patients in remission. In conclusion, we thought that it might not be practical to test de novo AML patients for JAK2V617F mutation, and studies on JAK2V617F mutation should be carried out on larger number of patients.