Multiple environmental factors and a multistage pathogenic mechanism appear to be involved in oropharyngeal carcinogenesis. Tobacco and alcohol are the most important risk factors, but other agents may also contribute to malignant transformation. Individual susceptibility to environmental carcinogens, although significant, is still incompletely understood. Based on our present-day knowledge of risk factors, prevention should be possible in about two thirds of all oropharyngeal cancers. It cannot be achieved, however, without both public and professional education. A rational approach to prevention of oropharyngeal cancer should start in school before habits are formed, continued throughout adolescence, and reinforced in adults. Reduction or elimination of risk factors is of prime importance. For those who cannot quit tobacco, a reduction of tar content in cigarettes, cigars, pipes, and chewing tobacco, and elimination of nitrosamines, especially from smokeless tobacco, might also help to reduce risks. Control of chronic alcoholism is more difficult, but diet supplementation, especially with proteins, vitamins, and trace metals, would decrease the promoter effect of alcohol. Control of occupational risks is of less significance. The clinician must have a state-of-the-art understanding of all known risk factors for the prevention, early detection, and control of oropharyngeal cancer. The history should review in detail exposure to tobacco, alcohol, actinic radiation, and other agents. Age of first exposure or onset of habit; duration (years); quantity of tobacco smoked, chewed, or snuffed; and its relationship with the anatomic site at risk should all be precisely recorded. Exposure to alcohol or any other risk factor should be evaluated in the same way. This review has emphasized the relationship between the various risk factors and the site prevalence of malignant lesions. Habits, customs, and cultures, as well as anatomic physiologic factors, all have a bearing on the actual target sites at which the carcinogen(s) and promotor(s) are brought in contact with the oral mucosa. Habits and customs vary widely, both geographically and among individuals. Dentists and physicians should be aware of these individual factors as they examine their patients.