The purpose of this work was to evaluate the normal lymphocyte phenotype in the bronchoalveolar lavage fluid (BALF). BAL was carried out in 12 untreated healthy nonsmoking volunteers and in 9 cigarette smokers. For the analysis of lymphocyte subsets by two-color flow cytometry, the monoclonal antibodies used were directed anti: CD3, CD4, CD8, CD16, CD19, D25, CD45, CD56 and anti HLA-DR. An increase in the total number of cells in BALF of smoking persons and increased proportion of macrophages was observed. The percentage of CD8+ lymphocytes was 1.7 times higher, whereas the proportions of CD4+ cells, and a CD4+/CD8+ ratio were lower 1.5 and 2.6 times, respectively, in the BALF of cigarette smoking persons when compared with nonsmoking volunteers. The changes did not depend on the age of the person. In conclusion, we suggest that the decreased CD4/CD8 ratio and the elevated CD8 T cell subset may be regarded as a potential risk factor associated with clinically asymptomatic lung cancer. Moreover, in the interpretation of BALF from patients with pulmonary diseases cell proportions of nonsmoking and of smoking persons should be compared with the respective controls.