Oral cancer is a common malignancy, ranking first among all cancers in Western and Asian countries. It is preceded by some benign lesions or conditions, which are termed precancerous. Only one-third of people at the precancerous stage of disease succumb to cancer, it would be of practical importance to identify individuals at risk among them. Biomarkers, instruments of individual tumor prevention, help to detect high-risk patents. The induction of micronucleus is considered to bean effective biomarker of diseases- In the recent past, a great deal of enthusiasm was raised by application of the micronucleus test to assess DNA damage in human population. The present study is aimed at the evaluation of frequency of micronuclei in smears of oral exfoliated cells. A total of 33 patients with potentially malignant (leukoplakia, OSMF, lichen planus) and malignant oral epithelial diseases from the department of oral medicine and radiology were considered as study group and compared with 33 age and sex matched healthy controls. Micronucleus frequencies were found higher in diseased patients than in control subjects- Hence, concluded that the micronucleus assay can be used as a prognostic indicator in potentially malignant and malignant disorders.