BACKGROUND Micronuclei (MN) in oral exfoliative cells have been shown to indicate a disparaging change in genetic information of the cell. Recent studies showed correlation between the frequency of MN and severity of this damage. Grading of lesions can be used to determine the austerity of this damage. Aims: The aim of this study is to compare the MN frequency in oral exfoliated cells of normal and oral squamous cell carcinoma (OSCC) individuals and to cytologically grade the frequency of MN in cytological smears and to correlate it with histological grading. The objective is to ascertain whether MN frequency in oral exfoliated cells can be a parameter for grading of OSCC. METHODS The study group comprises of 40 subjects (20 controls and 20 OSCC patients) in the age group of 45-85 years. METHODS The cytosmear was obtained from each group and stained with Papanicolaou (PAP) stain. Twenty cells from each slide were counted for MN and cytological grade of OSCC was assigned based on the average frequency of MN. Cytological grade was correlated with histological grading and the data were recorded. Student's t-test and Spearman's correlation were used for the analysis of the data. RESULTS Average frequency of MN was 2.5 times higher in OSCC patients when compared to that in controls and the difference was found to be highly significant. Sixty percent correlation was found between cytological grade and histological grade of OSCC and the difference between them was not significant. CONCLUSIONS Cytological grading can be used in grading OSCC, and MN insinuates genotoxic damage occurring in the epithelial cells.