Purpose of reviewMyeloproliferative neoplasms (MPN) are conditions of great interest because of the identification of their molecular basis and of the entering of new small molecules into clinical practice. The aim of this review is to report the role of mutations in the diagnosis, prognosis, and in the prediction of response to JAK inhibitors in MPN.Recent findingsNew mutations of the CALR gene have been discovered in patients without JAK2 or MPL mutations and are now included in the World Health Organization classification system. The role of ASXL1 and SRSF2 together with the driver mutations is emerging in the prognostication of myelofibrosis.SummaryA wide mutational analysis of MPN helps to define diagnosis and prognosis. In the future, clinical trials based on a robust valuation of mutations will guide treatment decision-making towards precision medicine.