Background: Oral cancer ranks the sixth commonest cancer worldwide and the third most common cancer in India. Ki67 index has been suggested to play an important role in early diagnosis and prognosis of potentially malignant disorders. This study aims to understand prognostic role of Ki 67 expression in different categories of oral mucosal neoplastic lesions in Central India, where tobacco chewing is endemic. This could help in early categorization and effective management of patients. Aims: To study the Ki67 expression in terms of Index of Positivity and Intensity score in oral mucosal neoplastic lesions. Setting and Design: Department of Pathology, Tertiary Care Hospital Observational & Prospective study Methods & Material: The expression of Ki-67was studied in parafn- embedded tissue sections of histopathology proven pre- malignant and malignant lesions of oral cavity in ninety four cases. Results: Association of Ki67 Expression Intensity score with the type of lesion was found to be signicant in premalignant and malignant lesions predominantly (p= <0.001).Similarly, Ki67 Index of positivity score was highly statistically signicant (p= <0.001) in association with the type of lesion. Conclusions: the expression of Ki-67 correlates well with the disease progression from dysplasia to carcinoma of the oral cavity. It is therefore a marker of malignant transformation and carcinogenesis in oral premalignant lesions and in future it may serve as a prognostic tool in the early detection of malignancy