Tumors arising from different sites of the head and neck area have very different clinical behavior. Loss or reduction of expression of adhesion molecules has been assumed to play a critical role in the development of head and neck carcinomas. The aim of this study is to determine if there are differences in the expression of adhesion molecules E-cadherin, CD44s, and CD44v6 in pharyngeal and laryngeal squamous-cell carcinomas. E-cadherin, CD44s, and CD44v6 expression was determined by immunohistochemistry in paraffin-embedded tissue specimens from 72 patients with squamous-cell carcinoma, 37 of the pharynx and 35 of the larynx. Expression of CD44s was significantly lower in pharyngeal than in laryngeal tumors (P =.01). No differences in the expression of E-cadherin and CD44v6 were observed between these sites. These data suggest that there are some differences at molecular level between the different subsites of head and neck cancer.