Both active and sham acupuncture had a beneficial effect on improving overactive bladder symptoms. Both significantly reduced the incontinence frequency, the daytime and night urinary frequency, as well as scores of Urinary Distress Inventory, Incontinence Impact questionnaire, and Overactive Bladder Symptom Score. The treatment effects could last for at least 3 months. The night urinary frequency decreased more significantly in the active acupuncture group than in the sham control group after controlling for baseline nocturnal micturitions. Adverse effects were mild. Further research is needed to investigate the placebo effect of acupuncture for overactive bladder.