Background: The progression of oral epithelial dysplastic lesions into oral squamous cell carcinoma is characterized by an ‘angiogenic switch’ which is characterized by an increase in neo-vascularization in the subepithelial lamina propria which can be considered an indicator of malignant transformation. Mast cells are a rich source of various angiogenic factors. Moreover mast cells secrete various proteolytic enzymes which degrade the extracellular matrix and create space for the developing blood vessels. Aims: This study was undertaken to determine the relationship between mast cell density and microvessel density in normal oral mucosa, oral epithelial dysplasia and oral squamous cell carcinoma and to find out whether any correlation exists between these two parameters. Material and Methods: This retrospective study was performed using formalin fixed, paraffin embedded tissues of previously diagnosed cases of oral epithelial dysplasia and oral squamous cell carcinoma. Mast cells were stained using toluidine blue, whereas in the capillaries, immunohistochemical staining technique was performed using mouse monoclonal antibody against CD34. Results: Mast cell density and microvessel density were higher in oral epithelial dysplasia and in oral squamous cell carcinoma compared to the normal mucosa. However, statistically significant positive correlation was noted only in oral epithelial dysplasia Conclusion: The above results probably indicate a role of mast cells in ‘angiogenic switch’. These angiogenic factors secreted by mast cells promote angiogenesis either directly by stimulating the migration and/or proliferation of mast cells or indirectly through degradation of extracellular matrix. Targeting the mast cells may contribute in preventing the progression of the lesion.