Background. A search for pathogenetically grounded approaches to the treatment of non-small cell lung cancer is undoubtedly one of the top priorities, because of the results of its treatment cannot be regarded as satisfactory. Discovery of a new type of receptors, estrogen receptors ß, that expressed in non-small cell lung cancer, created the preconditions for the development of a new treatment strategy for non-small cell lung cancer, namely antiestrogen therapy. Objective was to answer to the clinically significant question of how many patients with non-small cell lung cancer and lung metastases are potential candidates for antiestrogen treatment. Materials and methods. A comparative quantitative estimation of the level and frequency of the estrogen receptors ß expression in non-small cell lung cancer tissues and also in lung metastases (74 in total) was carried out by flow cytometry. Results. The estrogen receptors ß expression was detected in the majority of the investigated tumors and lung metastases, in 92 and 86 % of patients, respectively. The average level of estrogen receptors ß expression in non-small cell lung cancer tissue was higher then in metastases (42 % and 34.6 % respectively). The differences was statistically significant (p = 0.03). Primary tumors with a high and low+moderate estrogen receptors ß expression levels were detected in 35 % and 65 % of cases respectively and metastases with such expression levels - in 14 % and 86 % of cases respectively. Conclusion. 1. The estrogen receptors ß expression in the tumor predicts a more favorable course of the disease. One of the reasons for this may be a greater metastatic potential of tumor cells with low estrogen receptors ß expression. 2. The group of potential candidates for carrying out the adjuvant antiestrogen therapy comprises about 70 % of patients with primary lung tumors and with metastatic lesions of lung.