It has been more than 35 years since the Surgeon General of the United States released the first report of the Advisory Committee on Smoking and Health. Cigarette smoking has been identified as the most important source of preventable morbidity and premature mortality in North America. During the 1990s, tobacco was the largest single cause of premature death in the developed world. Smoking cessation is followed by immediate health benefits in terms of symptoms and organ function. It dramatically reduces the risk of most smoking-related diseases, including chronic obstructive pulmonary disease and lung cancer. Respiratory rehabilitation has been defined as a multidimensional continuum of services directed to persons with pulmonary disease and their families, usually by an interdisciplinary team of specialists, with the goal of achieving and maintaining the individual's maximum level of independence and functioning in the community. A European Respiratory Society task force on rehabilitation recently commented that respiratory rehabilitation must address medical management including reinforcement of smoking cessation, education of the patient and family, exercise reconditioning, physical and occupational therapy, nutritional support, and long-term oxygen therapy. Many patients have quit smoking by the time they enroll in a pulmonary rehabilitation program. Nevertheless, the inclusion of smokers in respiratory rehabilitation programs remains controversial. Among 14 trials included in a meta-analysis of respiratory rehabilitation of patients with chronic obstructive pulmonary disease (COPD), the smoking status of the patients was reported in 9 of the trials, and only 2 trials stated that smoking was an absolute exclusion criterion for enrollment. Some investigators have used a trial of smoking cessation as an index of the patient's motivation to improve his or her health status. This article describes the effect of smoking on the course of COPD and the opportunity to address smoking in the context of comprehensive rehabilitation. The authors' line of reasoning is that (1) smoking causes COPD and perpetuates the pathophysiologic processes defining the disease, (2) symptomatic COPD does not facilitate smoking cessation, (3) smoking may alter rehabilitation outcomes, and (4) if smoking cessation is not a prerequisite to pulmonary rehabilitation, then a smoking cessation intervention should at least he offered as part of such a program.