OBJECTIVE: To evaluate the efficacy of acupuncture in treating chronic fatigue syndrome (CFS) in Hong Kong. METHODS: A single-blinded, randomized controlled trial design was adopted. Participants meeting inclusion criteria were randomly assigned to a treatment and a control group according to 1:1 ratio, resulting in an effective sample size of 99, with 50 and 49 patients in treatment and control group respectively. The same set of acupuncture points, which were selected according to traditional Chinese medicine theories, was applied in both groups, while conventional needle acupuncture was applied in treatment group and sham acupuncture (without skin penetration) was applied in control group. Schedule of treatment was the same in both groups, i.e. twice a week for 4 weeks. Key outcome measures were Chalder's Fatigue Scale, diagnostic criteria for CFS of the US's Centre for Disease Control and SF-12 health-related quality of life (HQOL) questionnaire. Adverse events, if any, were recorded. RESULTS: Improvements in physical and mental fatigue and HQOL in both groups were observed, but the improvements in treatment group were significantly bigger than in control group (P<0.01 or P<0.05). No adverse events occurred. CONCLUSION: Acupuncture is a safe, effective treatment for CFS.