AIM: We evaluated the relationship between chronic obstructive pulmonary disease (COPD) assessment test (CAT) and improvements after pulmonary rehabilitation (PR) and PR efficiency in COPD patients. METHODS & RESULTS: Forty COPD patients completed PR. After PR, mean change in CAT score was found to be 13 (p < 0.001), Medical Research Council (MRC), St George's Respiratory Questionnaire (SRGQ) and London Chest Activity Daily Living (LCADL) scores decreased, while Endurance Shuttle Walking Test (ESWT) time and Incremental Shuttle Walking Test (ISWT) distance increased significantly. Baseline CAT scores correlated with MRC, SRGQtotal, %FVC, ISWT, ESWT, LCADL. Change in CAT was significantly correlated with changes in MRC, SGRQtotal, LCADL-leisure scores, and ESWT. CONCLUSION: CAT score shows moderate degree correlation with some measures of outcome of PR and response to PR efficacy.