The purpose of this review was to determine the impact of duration of pulmonary rehabilitation on measures of health-related quality of life and exercise tolerance in individuals with chronic obstructive pulmonary disease (COPD). Randomized controlled trials (RCTs) comparing different lengths of pulmonary rehabilitation in patients with COPD were identified after searches of six electronic databases (MEDLINE, PubMed, CINAHL, EMBASE, Physiotherapy Evidence Database [PEDro] and the Cochrane Library of clinical trials) and reference lists of pertinent articles. Two reviewers performed the searches and assessed trial quality using PEDro and Jadad scales. Five RCTs met inclusion criteria. The mean PEDro score was 6 (range 3-8) and mean Jadad was 2 (range 1-3). Three trials reported a difference in health-related quality of life in favour of the longer duration program; two trials reported a benefit in exercise capacity in favour of longer programs. A meta-analysis of results was not possible due to considerable heterogeneity in program duration and outcomes. Longer duration pulmonary rehabilitation programs appear to have a more favourable effect on health-related quality of life in individuals with COPD; results for exercise capacity are less clear. The limited literature prevents a more definitive conclusion on optimal duration of rehabilitation.