Snuff-induced oral lesions were studied clinically, histologically and by electron microscopy. The material was collected from 21 male snuff users. The lesions had a characteristic whitish appearance with a wrinkled swollen texture and the most common localization was in the vestibular area of the upper jaw. In two cases gingival retraction was observed. The light-microscopical examination showed a mild epithelial dysplasia in five cases. No carcinoma in situ or invasive carcinoma was recognized. In some of the cases ultrastructural changes in the basement lamina region, such as defects of the basement lamina and the occurrence of basal cell processes in the connective tissue, were observed. Odland bodies were seen in the epithelium. In the connective tissue filamentous material of unknown nature was found. The ultrastructure of the filamentous material suggested that it might be amyloid. In summary, snuff-induced lesions should be diagnosed, patients should be informed and made to quit the habit, and remaining lesions should be followed up regularly.