To compare the effects of comprehensive pulmonary rehabilitation with those of education alone on physiologic and psychosocial outcomes in patients with chronic obstructive pulmonary disease. Randomized clinical trial. University medical center. 119 outpatients with chronic obstructive pulmonary disease that was stable while patients received a standard medical regimen. Patients were randomly assigned to either an 8-week comprehensive pulmonary rehabilitation program or to an 8-week education program. Pulmonary rehabilitation consisted of twelve 4-hour sessions that included education, physical and respiratory care instruction, psychosocial support, and supervised exercise training. Monthly reinforcement sessions were held for 1 year. The education group attended four 2-hour sessions that included video-tapes, lectures, and discussions but not individual instruction or exercise training. Pulmonary function, maximum exercise tolerance and endurance, gas exchange, symptoms of perceived breathlessness and muscle fatigue with exercise, shortness of breath, self-efficacy for walking, depression, general quality of well-being, and hospitalizations associated with pulmonary diseases. Patients were followed for 6 years. Compared with education alone, comprehensive pulmonary rehabilitation produced a significantly greater increase in maximal exercise tolerance (+1.5 metabolic equivalents [METS] compared with +0.6 METS [P < 0.001]; maximal oxygen uptake, +0.11 L/min compared with +0.03 L/min [P = 0.06]), exercise endurance (+10.5 minutes compared with +1.3 minutes [P < 0.001]), symptoms of perceived breathlessness (score of -1.5 compared with +0.2 [P < 0.001]) and muscle fatigue (score of -1.4 compared with -0.2 [P < 0.01]), shortness of breath (score of -7.0 compared with +0.6 [P < 0.01]), and self-efficacy for walking (score of +1.4 compared with +0.1 [P < 0.05]). There were slight but nonsignificant differences in survival (67% compared with 56% [P = 0.32]) and duration of hospital stay (-2.4 days/patient per year compared with +1.3 days/patient per year [P = 0.20]). Measures of lung function, depression, and general quality of life did not differ between groups. Differences tended to diminish after 1 year of follow-up. Comprehensive pulmonary rehabilitation significantly improved exercise performance and symptoms for patients with moderate to severe chronic obstructive pulmonary disease. Benefits were partially maintained for at least 1 year and tended to diminish after that time.