Cigarette smoking is a major cause of illness and premature death in our society. Secondhand smoke is a definite irritant to nonsmokers and can, under certain conditions, have potentially serious effects on the nonsmoker's health. Despite the facts, millions of persons continue to smoke. Although no single health professional reaches all smokers, the dentist has a particularly good opportunity to reach his patients who smoke. By advising and couseling, providing helpful literature, creating an environment in which smoking is prohibited, and setting a good example, the dentist can have a singificant part in his patients' education on cigarette smoking. If the dentist's efforts are even partially successful in modifying behavior of the patient who smokes, much illness will be avoided and many lives saved.