Ruxolitinib, a Janus kinase inhibitor, considerably improves symptoms of patients with polycythemia vera and primary or secondary myelofibrosis. However, its association with the development of infectious complications is a concern. Herein, we report the case of an 80-year-old man with primary myelofibrosis who developed disseminated tuberculosis during treatment with ruxolitinib at 15 mg twice daily and prednisone at 5 mg. We also reviewed the literature on patients who developed tuberculosis during treatment with ruxolitinib. There are 13 case reports of patients who developed tuberculosis during treatment with ruxolitinib, including our case. Disseminated tuberculosis manifestations were observed in 84.6 % of the patients and 50 % of them died. Although the interferon-gamma release assay was performed for seven of the patients with six positive results at the time of tuberculosis diagnosis, none were tested before the commencement of ruxolitinib. We suggest taking a history of tuberculosis and screening for and treating latent tuberculosis before administering ruxolitinib, especially in areas where the risk of tuberculosis is high.