The Micronuclei frequency in tobacco chewers seem to increase steadily as the genotoxic damage increases and progresses from premalignant to malignant oral lesions. This can be easily evaluated in exfoliated oral epithelial cells and helps in assessing the severity. This study was taken up with the objective to assess the frequency of micronuclei (MN) in buccal smear of tobacco chewers with healthy mucosa, premalignant and malignant oral lesions and compare all these cases with that of healthy individuals. The study subjects were divided into four groups each consisting of 20 individuals. The groups were cases with healthy oral mucosa, second group with premalignant oral lesions, third with malignant oral lesions in tobacco chewers and last group with normal controls. The exfoliative cytological smears were stained with Papanicolaou stain. The micronuclei frequency was identified using Tolbert’s criteria. The micronuclei were found to increase in frequency in cases as compared with controls. There was a significant increase from apparently healthy tobacco chewers to premalignant and malignant oral lesions. Hence, micronuclei can be used as a screening tool in tobacco chewers to assess the potentiality of carcinoma and thus a useful diagnostic as well as prognostic indicator.