Epithelial-mesenchymal transition (EMT) can play an important role in carcinogenesis of oral squamous cell carcinoma (OSCC). EMT is characterized by morphological and phenotypical change of epithelial cells into mesenchymal cells, and transcriptional repressor of E-cadherin, Snail is critical for EMT. In order to investigate the role of Snail and E-cadherin in OSCC, we analyzed the immunohistochemical pattern of Snail and E-cadherin in 18 OSCCs. The expression of Snail in the OSCC was increased whereas the expression of E-cadherin in the OSCC was decreased in comparison with those of normal oral mucosa, showing reverse correlation. Especially, the fibroblasts near the islands of OSCC showed the positivity of Snail, suggesting the reactive fibroblasts to the EMT of epithelial tumor cells. In metastatic squamous cell carcinoma in cervical lymph node, the positivity of Snail of tumor cells was higher than that of primary OSCC. We concluded that the increased Snail expression and the decreased E-cadherin expression were involved in the progression, invasion and metastasis of OSCC.