Background: Alteration of cadherin and catenin expression is associated with loss of differentiation, acquisition of an invasive phenotype, and poor prognosis in many types of cancers. The roles of cadherins and catenins in mucoepidermoid carcinoma (MEC) are not fully understood. Methods: Based on immunohistochemical studies, the expressions of E-, N-, and P-cadherins and α, β, and γ-catenins in MEC were investigated, and correlations with clinicopathologic parameters were evaluated. Results: These six molecules were strongly expressed in normal ductal epithelium but increased or decreased immunoreactivities of those proteins in MEC were frequently observed, especially for E-cadherin and α-catenin. The immunoactivity of β-catenin showed significant correlation with grade (P=0.05) and stage (P<0.0001). β-Catenin expressions are also correlated with γ-catenin expression (P=0.006) according to cross-table analysis. Survival analysis indicated that stage, grade, and β-catenin expressions had significant correlation with survival. Conclusion: Aberrant β-catenin expression may play an important role in the histologic differentiation and tumor staging of MEC.