The present study was carried out in order to evaluate whether precancerous lesions could be detected in the nasal mucosa of furniture workers. Histological examination of nasal biopsies from 113 workers (103 active and 10 retired) and 54 referents was performed. The histological sections were evaluated blindly according to a numerical classification scale, and the results were compared, by means of multiple regression analysis, to age, type and duration of exposure to wood dust, smoking habits, nasal allergy, and rhinoscopic findings. Nasal stenosis and mechanical wood preparation were significantly related to the histological findings by the partial correlation coefficients. Fourteen cases (12%) of dysplasia were found among the furniture workers, preferentially among those performing mechanical wood preparation, and among the referents there was one (2%). The evaluation of the importance of exposure to dust of individual types of wood was not possible. Nasal epithelial dysplasia should probably be interpreted as a preneoplastic lesion and may be of significance in the pathogenesis of nasal adenocarcinoma. Standard nasal biopsies appear to be valuable in identifying groups of persons with an increased incidence of nasal carcinoma.