Deficits in balance are increasingly recognized among the important secondary impairments in COPD. The purpose of this study was to investigate the effect of a balance-training program on measures of balance and physical function in patients with COPD enrolled in pulmonary rehabilitation (PR). Patients were assigned randomly to an intervention or control group. The intervention group underwent balance training three times a week for 6 weeks concurrently with PR. The control group received only the 6-week PR program. Clinical balance measures included the Berg Balance Scale (BBS), the Balance Evaluation Systems Test (BESTest), and the Activities-Specific Balance Confidence (ABC) scale. The physical function subscale of the 36-Item Short Form Health Survey (PF-10) and the 30-s chair-stand test were used to measure self-reported physical function and lower-extremity muscle strength, respectively. Thirty-nine patients with COPD (mean FEV1, 37.5% ± 15.6% predicted) were enrolled in the study. Mean compliance with the balance-training program was 82.5%, and no adverse events were reported. Compared with control subjects, scores on the BBS (P < .01), BESTest (P < .01), PF-10 (P = .01), and 30-s chair-stand (P = .02) were significantly improved in the intervention group. No significant between-group differences were found in change scores on the ABC scale (P = .2). Our results support the feasibility and effectiveness of balance training as part of PR for improving balance performance, muscle strength, and self-reported physical function in patients with moderate to severe COPD.