Ruxolitinib (Jakavi(®), Jakafi(®)) is an orally administered inhibitor of Janus kinases (JAK) 1 and 2 used in the management of patients with myelofibrosis. Clinical trials with ruxolitinib, notably the phase III COMFORT-I and -II studies and their extensions, have demonstrated marked and durable clinical benefits in terms of reductions in splenomegaly and disease-related symptoms in patients with intermediate-2 or high-risk myelofibrosis. Ruxolitinib was also associated with improvements in health-related quality of life and functioning. Despite the crossover of patients in control groups to ruxolitinib, results of the COMFORT studies and their extensions indicate a survival advantage for patients randomized to ruxolitinib. The beneficial effects of ruxolitinib were observed across subgroups of myelofibrosis patients, including those not harbouring the JAK2V617F mutation. Improvements in splenomegaly and disease-related symptoms were also observed in a trial in Japanese/Asian patients with myelofibrosis and in myelofibrosis patients with a low baseline platelet count. Dose-related anaemia and thrombocytopenia were common in clinical trials with ruxolitinib, but rarely led to discontinuation of therapy and were managed with dosage modifications and/or transfusions of packed red blood cells. In addition to the USA and EU, ruxolitinib is now approved in a number of other countries, including Japan, and remains the only approved drug for the treatment of myelofibrosis, although various other agents are undergoing investigation. Appropriate monitoring and dosage titration are important to achieve optimal clinical benefits of ruxolitinib. Further research, including studies evaluating ruxolitinib-based combination therapy, may also help to optimise treatment.