PURPOSE: Although physicians generally reserve pulmonary rehabilitation (PR) referral for patients in later stages of chronic obstructive pulmonary disease (COPD), there is no evidence to suggest that PR programs are more effective for these persons than for those in earlier stages of the disease. This study examined the relationship between 6-minute walk change and COPD stage in patients completing PR. METHODS: The sample consisted of 76 patients who enrolled in the University of Alabama at Birmingham's Cardiopulmonary Rehabilitation Program with a primary diagnosis of COPD between January 1996 and June 2000. Data was collected on 6-minute walk upon entry into the program and upon program completion. Patients were stratified according to COPD stage using the American Thoracic Society staging system. RESULTS: There were significant differences among the three stages with regard to initial and ending 6-minute walk distances such that persons in later stages of the disease have shorter initial and ending 6-minute walk distances. However, all three stages show significant improvements in the 6-minute walk after PR. There were no significant differences in the median change among groups indicating that the median change was not better (or worse) for patients in any particular COPD stage. CONCLUSIONS: This study suggests that PR is equally effective in increasing physical performance for all patients regardless of COPD stage. This type of information can be used to support the recommendation of PR for patients early in the disease process.