Physicians play critical roles in efforts to encourage nonsmoking, both in their individual interventions with smokers and in their contributions to broader political, educational, and public health efforts to encourage nonsmoking. These broader efforts, much aided by the authority and concern of individual physicians and organized medicine will continue, also, to provide a supportive background for individual clinical efforts. Together, the broad based and the clinical activity potentiate each other in decreasing the prevalence of smoking. The difficulties individuals experience in quitting smoking are best understood when placed within the context of the billion dollar marketing of an addictive product; the reality that quitting smoking occurs gradually over time, many smokers attempting to quit several times before succeeding; and the influence of physicians' continuing clinical and community activity in maintaining a culture actively cognizant of the risks of smoking. Through brief clinical counseling as outlined in this article, physicians can help almost all of their smoking patients move toward becoming a nonsmoker by trying to quit or, at least, giving greater thought to doing so. Additionally, the physician can help patients eager to quit by referral to well developed programs and materials such as have been described. In all, then, numerous effective resources are available for the clinician who wishes to deal responsibly with the most important preventable cause of morbidity and mortality in the approximately 30 per cent of patients who smoke.