The prognosis of the oral squamous cell carcinoma (OSCC) patients remains very poor, mainly due to their high propensity to invade and metastasize. E-cadherin reduced expression occurs in the primary step of oral tumour progression and gene methylation is a mode by which the expression of this protein is regulated in cancers. In this perspective, we investigated E-cadherin gene (CDH1) promoter methylation status in OSCC and its correlation with Ecadherin protein expression, clinicopathological characteristics and patient outcome. Histologically proven OSCC and paired normal mucosa were analyzed for CDH1 promoter methylation status and E-cadherin protein expression by methylation-specific polymerase chain reaction and immunohistochemistry. Colocalization of E-cadherin with epidermal growth factor (EGF) receptor (EGFR) was evidenced by confocal microscopy and by immunoprecipitation analyses. This study indicated E-cadherin protein down-regulation in OSCC associated with protein delocalization from membrane to cytoplasm. Low E-cadherin expression correlated to aggressive, poorly differentiated, high grade carcinomas and low patient survival. Moreover, protein down-regulation appeared to be due to E-cadherin mRNA downregulation and CDH1 promoter hypermethylation. In an in vitro model of OSCC the treatment with EGF caused internalization and co-localization of E-cadherin with EGFR and the addition of demethylating agents increased E-cadherin expression. Low E-Cadherin expression is a negative prognostic factor of OSCC and is likely due to the hypermethylation of CDH1 promoter. The delocalization of E-cadherin from membrane to cytoplasm could be also due to the increased expression of EGFR in OSCC and the consequent increase of E-cadherin co-internalization with EGFR.