BACKGROUND Traditional acupuncture has been used in patients with chronic obstructive pulmonary disease (COPD). However, only a few studies have been performed to determine the efficacy of this treatment. OBJECTIVE To observe changes in the symptoms of COPD during acupuncture treatment in patients with COPD stratified according to the severity of the disease. METHODS A prospective case series of 26 patients with dyspnoea on exertion due to COPD was followed from October 2004 to October 2008 in the Departments of Respiratory Internal Medicine, Gifu University of Medicine and Meiji University of Integrative Medicine, Japan. All participants received acupuncture treatments once a week for 10 weeks in addition to standard medication therapy. The main outcome measure was the modified Borg dyspnoea scale after the 6 min walk test (6MWT) and the secondary outcome measure was the BODE index. RESULTS All 26 patients showed significant improvement in the Borg dyspnoea scale after 10 weeks of acupuncture treatment (from 4.02 (2.85) to 1.96 (1.97), mean difference -2.06, 95% CI -3.03 to -1.09, p=0.0002, paired t test). Improvements in the BODE index, 6MWT and oxygen saturation during exercise, which indicates better reduced dyspnoea on exertion and prognosis, were also found. CONCLUSION The results of this study suggest that acupuncture treatment has clinically useful effects, at least in the short term, in reducing dyspnoea on exercise in patients with COPD, particularly in those more severely affected.