BACKGROUND The c-erbB-2 gene codes for a putative transmembrane protein, similar in structure to the epidermal growth factor receptor. Amplification and/or overexpression of the gene has been recently described with a prognostic significance in a variety of human adenocarcinomas. METHODS A monoclonal antibody against the c-erbB-2 oncoprotein has been used immunocytochemically in a retrospective study of formalin-fixed, paraffin-embedded samples from 28 consecutive intestinal-type adenocarcinomas (ITACs) of the nose and paranasal sinuses. RESULTS Nine out of 28 primary adenocarcinomas (32%) showed positive staining. Clinical follow-up data, available for all patients, suggested in a univariate analysis a correlation between c-erbB-2 expression and poor prognosis, as measured by 5-year disease-free (p = .02) and overall survival curves (p = .07) as well as by recurrence of disease and the appearance of regional and distant metastases (p = .08). In multivariate analysis, c-erbB-2 expression was statistically significant in terms of disease-free survival (p = .046) but not of overall survival (p = .091) in our series. CONCLUSIONS These data indicate that c-erbB-2 oncogene activation could be involved in sinonasal tract oncogenesis, with possible prognostic implications.