The purpose was to assess chromosomal damage in blood mononuclear cells of smokers. Smoker’s peripheral blood samples were screened for micronuclei. Samples from smokers who had an illness were excluded. From each sample, 500 swelled mononuclear leucocytes were screened using a light microscope, with 400x magnification. Frequency distribution of subjects having 0, 1, 2, 3, 4, and 5 micronuclei (MN) according to age and condition were tabulated. From the 102 samples, 5 were excluded, and only 97 were analyzed. There was an increase in MN count in 12.8%, 12.9%, 33.3%, and 25% of normal smokers living in unpolluted area, hypertensive smokers living in unpolluted area, normal smokers living in polluted area, and hypertensive smokers living in polluted area, respectively. Therefore, there was a tendency of increasing MN count in smokers in the productive age group, hypertensive people, and people living in polluted area.