Until recently, the use of smokeless tobacco had been restricted to a relatively small percentage of the United States population. The increased promotion and use of both snuff and chewing tobacco raise the question: What effect will such habits have on oral disease and the incidence of oral cancer? Although information for the US is sparse, extensive epidemiologic data are available from India, where the use of tobacco is prevalent and the incidence of oral cancer very high. The Indian data suggest that oral cancer and precancerous lesions occur almost solely among those with tobacco habits, the rate of malignant transformation of precancerous lesions is not greater than in the West, the relative risk of developing oral cancer is similar in India and in the US, and this risk rises with duration of use. Thus, it seems likely that increased usage of smokeless tobacco in the US will eventually lead to an increased incidence of precancerous and cancerous oral lesions in Americans.