JAK2 V617F mutation is a common event in chronic myeloproliferative disorders. However, de novo acute myeloid leukemia with JAK2 V617F is rarely encountered. The authors report the case of a 74-year-old male with de novo acute myeloblastic leukemia without maturation (AML M1) and a JAk2 V617F heterozygotic mutation. Despite treatment with standard AML regimens, the patient died 2 months after a diagnosis of acute leukemia. This case of an AML patient with a JAK2 V617F mutation with a poor prognosis suggests that despite its rarity, a JAK2 V617F mutational study be considered for prognostic purposes in AML.