Regional lymph node metastasis is a very important prognostic indicator. In the metastatic process, reduction in cell to cell adhesion including E-cadherin-catenin cell adhesion complex is an essential step. We investigated immunohistochemical expression of E-cadherin, alpha-catenin and beta-catenin in 159 tissue samples from patients with oral squamous cell carcinoma and examined the correlation between their expressions and the presence of regional lymph node metastasis. Significantly greater reduction in expression levels of E-cadherin, alpha-catenin and beta-catenin was found in the metastatic group (n=64) compared to the nonmetastatic group (n=95) (P=0.007, 0.001, 0.001, respectively). However, there was no significant correlation between their expressions and the features of the regional metastasis, the number of metastatic lymph nodes or the presence of extracapsular metastasis. These data suggest that evaluation of the immunohistochemical expression of E-cadherin, alpha-catenin and beta-catenin is extremely valuable for the diagnosis of metastatic occurrence.