The genotoxic damage that Tobacco smoke produces in smoker individuals was evaluated using the micronucleus assay in exfoliated buccal cells. The study comprises 90 individuals of which 46 were smokers and 44 were nonsmokers. We found the mean of the micronuclei frequency in exfoliated buccal cells was (10.18±1.07; 12.89±1.85) in nonsmoker and smoker individuals respectively, which is substantially higher than the baseline of the micronuclei expression in the general healthy population. There was a statistically significant difference in the micronuclei expression between smokers and non-smokers (P< 0.05). The mean value of micronucluei frequency in youngest age group (20-30) years was (14.27±1.63); in oldest age group (31-40) it was (9.75±0.87), the difference was significant (P< 0.01). We concluded that the higher frequency of micronuclei directly associated with the decrease of efficiency of DNA repair and increase of genomic instability. Micronucleus assay in the buccal cell is sensitive, practical, inexpensive method for monitoring genetic damage in human. Further researches are needed not only for count micronuclei but also to capture the frequency of apoptosis and necrosis cells to detect the further evaluation of cellular and tissue level biological damage.