The aim was to evaluate the expression of E-cadherin and Vimentin in oral epithelial dysplasia (OED) and oral squamous cell carcinoma (OSCC), in comparison with normal oral mucosa (NOM) in a descriptive case study using immunohistochemistry. A total of fifty-one (N=51) histological samples were included; as follows: n = 16 (NOM), n = 16 (OED) and n = 19 (OSCC). All samples were analyzed using immunohistochemistry against the expression of E-cadherin and Vimentin. Immunostaining was qualitatively evaluated by extent and intensity of its expression for E-cadherin and intensity for Vimentin. Extension and intensity analysis of E-cadherin and Vimentin immunostaining according to group revealed a statistically significant association (r<0.001). E-cadherin expression was found to be highest in NOM followed by OED and lowest in OSCC, inverse to what was observed with Vimentin. The present study revealed the down regulation of the molecular marker E-cadherin, suggestive of reduction in dysplastic cells on comparison to NOM cells, and aberrant expression of the mesenchymal marker Vimentin by epithelial cells in samples of NOM, OED and OSCC; questioning their value as a prognostic marker.