BACKGROUND: Currently incidence and prevalence of sarcoidosis are increasing. Sarcoidosis is a systemic granulomatous lung disease of unknown aetiology, which is characterised by the involvement of different organ systems, variable disease course affecting young people and possessing an important issue in the modern world. The disease is extremely heterogeneous with an unpredictable clinical course. Interesting clinical cases are described in which, with a sufficient illustration of the stages of the course and diagnosis of sarcoidosis of the lungs and peripheral lymph nodes, the diagnosis was difficult. Late diagnosis and lack of correct therapy make prognosis in patients with lung sarcoidosis unfavourable. AIM: To conduct a morphometric study with the determination of the cellular composition of granulomas for the differential diagnosis of morphogenesis of granulomas in sarcoidosis and pulmonary tuberculosis. MATERIAL AND METHODS: An analysis of transthoracic biopsy of 89 patients with a verified diagnosis of sarcoidosis of the lungs and disseminated form of pulmonary tuberculosis was carried out. The resulting lung tissue material was carried out according to the standard histological method; conducted morphometric analysis. RESULTS: Sarcoid granulomas are characterised by an increase in lymphocytes, indicating the immune character of the lesion, an increase in fibroblasts, fibrocytes, and signs of activation of angiogenesis. While for TB granuloma an increase in the number of granulocytes and epithelioid cells is characteristic. These morphological criteria for the diagnosis of sarcoidosis of the lungs and lymph nodes are necessary for use in the practice of pathologists to verify the clinical diagnosis. CONCLUSION: Developed morphological and morphometric criteria for the differential diagnosis of sarcoidosis and pulmonary tuberculosis must be used in the practice of a pathologist to verify the clinical diagnosis, which will determine the adequate tactics of examination, administration, correction of the disease, and evaluation of the prognosis of the disease, taking into account identified clinical and laboratory data, results of instrumental research methods.