Aim To evaluate the influence of comorbidities and aging on pulmonary rehabilitation (PR) efficacy in patients with chronic obstructive pulmonary disease (COPD). Methods This was a retrospective cohort study of patients with COPD attending an outpatient PR program. Comorbidity information was collected with the Charlson Index, BODE index and COPD‐specific comorbidity test, and also included other common conditions not included in these indexes. The efficacy of PR was defined as a 54‐m increase in 6‐min walk distance or a four‐point decrease in St. George's Respiratory Questionnaire score. Patients were divided into two age groups according to the median age of 72 years. Results A total of 21 of 52 patients (40%) showed a clinically significant benefit by the 6‐min walk distance, and 29 patients (55.8%) by the St. George's Respiratory Questionnaire score. PR efficacy was not different between the elderly group and the younger group by either parameter. A total of 98% of the patients had at least one chronic comorbidity. Hypertension was the most frequently reported comorbidity (28.5%). Higher body mass index, Hospital Anxiety and Depression Scale anxiety score and St. George's Respiratory Questionnaire total score were associated with a good response to PR by the 6‐min walk distance. None of the individual comorbidities or indexes were correlated with the efficacy of PR. Multiple logistic regression analysis showed that body mass index was independently associated with the response to PR. Conclusions PR is equally effective in elderly and younger patients with COPD, with efficacy influenced by body mass index and anxiety. Geriatr Gerontol Int 2016; 16: 934–941.