Background. Many previous studies have shown the potential therapeutic effect of acupuncture for metabolic syndrome (MetS). However, most of these studies were limited by short durations of observation and a lack of sham acupuncture as control. We designed a randomized controlled trial, used sham acupuncture as the control, and evaluated the efficacy over 12 weeks of treatment and 12 weeks of follow-up. Methods/Design. The study was designed as a multicentre, parallel-group, randomized, double-blinded trial. 40 patients were randomly assigned to two groups: treatment group (treated with acupuncture) and control group (treated with sham acupuncture). Outcomes were measured at 4, 8, and 12 weeks and 3 months after treatment. Results. 33 participants (17 in acupuncture group and 16 in control group) completed the treatment and the follow-up. Decreases from baseline in mean waist circumference (WC) and weight at the end of treatment were 4.85 cm (95% CI [2.405,5.595]) and 4.00 kg (95% CI [1.6208,4.4498]) in acupuncture group and 1.62 cm and 1.64 kg in control group (P<0.01). The changes in mean glycosylated haemoglobin (HbA1c), triglycerides (TG), total cholesterol (TC), and blood pressure in acupuncture group were greater than the changes in control group (P<0.05, P<0.01). Conclusion. Acupuncture decreases WC, HC, HbA1c, TG, and TC values and blood pressure in MetS.