Despite their histological resemblance to colorectal adenocarcinoma, there is little information on the molecular events involved in the pathogenesis of intestinal-type sinonasal adenocarcinoma (ITACs). The aim of this paper is to evaluate the possible role of TP53 and Bcl-2 gene defects in ITAC by investigating the immunohistochemical expression of TP53 and Bcl-2 gene products in a group of ethmoidal ITACs associated with occupational exposure. A retrospective study on 15 patients with pathological diagnosis of primary ethmoidal ITAC was conducted. Representative formalin-fixed, paraffin wax-embedded block from each case was selected for immunohistochemical studies using the antibodies against p53 and Bcl-2. Clinical-pathological data were also correlated with the staining results. The results of immunohistochemical examination demonstrated that poorly differentiated cases showed a higher percentage of p53 and Bcl-2 expressing cells in comparison to well-differentiated cases. No correlation was found with other clinico-pathological parameters, including T, stage and relapses. The relationship between up-regulation of p53 and Bcl-2 and poorly differentiated ethmoidal adenocarcinoma suggests a role of these genes, in combination with additional genetic events, in the pathogenesis of ITAC.