Objectives. Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) affect individuals older than 50 years of age and corticosteroids are the mainstay of treatment. The aim of our study was to explore the role of leflunomide as a corticosteroid-sparing agent in GCA and PMR patients. Methods. Patients with difficult-to-treat GCA and PMR were retrospectively identified in the period from 2010 to 2013. The doses of corticosteroids and CRP values were noted before, after three months, and at the end of the treatment with leflunomide (for patients continuing treatment, censoring date was January 1, 2013). Results. Twenty-three patients were identified (12 with PMR and 11 with GCA). A reduction of 6 mg/dL (CI 95% –10.9–34.2, P = 0.05) in CRP and 3.7 mg (CI 95% 0.5–7.0, P = 0.03) in prednisolone dose was observed in the PMR group. In GCA patients, the reduction was 12.4 mg/dL (CI 95% 0.7–25.5, P = 0.06) in CRP and 6.6 mg (CI 95% 2.8–10.3, P < 0.01) in prednisolone dose. Conclusion. Leflunomide seems to be effective as a corticosteroid-sparing agent in patients with difficult-to-treat GCA and PMR. Randomized controlled trials are warranted in order to confirm the usefulness of leflunomide in the therapy of GCA/PMR.