Pulmonary rehabilitation is one of the most important treatment modalities for patients with chronic lung disease. To determine the effects of an outpatient pulmonary rehabilitation program for the older members (aged 77 +/- 3 years; seniors) of an elderly patient group with chronic lung disease, we prospectively compared the degrees of improvement of lung function, dyspnea, daily activities and exercise tolerance (6-minute walking distance) after a 9-week rehabilitation program in 27 seniors with chronic lung disease (COPD 18, post-tuberculosis lung disorders 8, lung fibrosis 1; %FEV1 50.9 +/- 17.1%) with that in disease- and %FEV1-matched younger members (aged 70 +/- 2 years; juniors; %FEV1 49.3 +/- 16.1%) of the elderly patient group. All patients performed supervised weekly outpatient exercise and education activities for 9 weeks and a home exercise regimen. Assessments were made before and after the program. Twenty-three of the seniors and 25 of the juniors completed the program. There was no significant difference in the withdrawal rates between these groups. Although lung function and blood gas data had not changed significantly after rehabilitation, the clinical symptoms and the 6-minute walking exercise improved significantly in both groups (Baseline Dyspnea Index focal score: +1.3 +/- 0.9 in the seniors and +0.6 +/- 0.9 in the juniors: 6-minute walking distance: +/- 52 m and +/- 62 m, respectively) and the improvement of the Baseline Dyspnea Index focal score was significantly greater in the seniors than in the juniors. We observed the patients after they had followed the program for 2,000 days and found that the continuation ratio of rehabilitation in the seniors was far inferior to that in the juniors (continuation ratios for 1.2 and 3 years in the seniors were 50.5, 18.0 and 0%, respectively, and in the juniors, 79.5, 66.2 and 61.5%). We concluded that, although the senior elderly patients could benefit from the pulmonary rehabilitation program, it is difficult to maintain this benefit for many years.