Patients who have contraindications to the prescription of GCs (glucocorticosteroids), or have developed serious side effects during treatment with GCs, as well as patients with resistance to GCs therapy, are prescribed immunosuppressants.The aim of the research - to study the efficacy of leflunomide monotherapy in patients with pulmonary sarcoidosis with contraindications to prescription or serious side effects of glucocorticosteroids.Fourteen patients with sarcoidosis of the respiratory system of stage II were examined – 12 women and 2 men aged 30 to 69 years. In 10 patients there were contraindications to the appointment of GCs (diabetes mellitus – 5, hypertension – 3, obesity – 1, exacerbation of gastric ulcer – 1), which caused the appointment of immunosuppressive therapy as a starting. In 4 cases, serious side effects of SCs were noted, requiring the drug to be abolished (osteoporosis – 3, steroid diabetes – 1). Leflunomide was administered at a dose of 20 mg per day, daily for 3 months. The evaluation of efficacy was carried out using computed tomography of the thoracic cavity organs, body plethysmography, spirometry and determination of the diffusivity of the lungs.Monotherapy with leflunomide in patients with contraindications to prescription or serious side effects of GCs was successful in 7 out of 13 patients, in 2 patients there was a stabilization of the process, in 4 patients with leflunomide therapy progression of the disease was noted and in 1 case the treatment was discontinued due to serious side effects of preparation.The results obtained make it possible to recommend the use of leflunomide as monotherapy in patients with pulmonary sarcoidosis with contraindications to the prescription and/or poor tolerability of GCs and methotrexate. It is necessary to continue studying the possibilities of combined use of leflunomide with other drugs of the first line.