Lung sarcoidosis is a generalized granulomatous disease with an unknown etiology, often accompanied by mediastinal lymphadenopathy. One of the methods helpful in differential diagnosis of sarcoidosis is the cytological evaluation of the material originating from the respiratory tract, and determining the ratio of helper T cells (CD4) to suppressor/cytotoxic T lymphocytes (CD8). The aim of the study was a cytometric evaluation of the material from the transbronchial lymph node biopsy, taken using the TBNB‑EBUS technique (called transbronchial nodi biopsy), and assessment of its usefulness in the diagnosis of patients with lung sarcoidosis. The diagnosis of sarcoidosis was made in 12 of 23 studied patients with mediastinal lymphadenopathy. In patients with pulmonary sarcoidosis an increased percentage of CD8+ lymphocytes was found significantly more often (19.34% ±7.98%, median 19.8%) in the examined material. However, symptoms of arthritis were significantly more frequent in patients with an increased percentage of CD3+ T lymphocytes (64.49% ±11.9%, median 65.85%). The study showed that flow cytometry of cytological material with TBNB‑EBUS in conjunction with clinical data is useful in the diagnosis of lung sarcoidosis.