Objectives. This study aimed to evaluate the efficacy and safety of manual acupuncture as a prophylaxis for frequent migraine. Methods. Fifty frequent migraineurs were randomly allocated to receive 16 sessions of either real acupuncture (RA = 26) or sham acupuncture (SA = 24) during 20 weeks. The primary outcomes were days with migraine over four weeks, duration, and intensity of migraine and the number of responders with more than 50% reduction of migraine days. The secondary outcomes were the relief medication, quality of migraine, quality of life, and pressure pain thresholds. Results. The two groups were comparable at baseline. At the end of the treatment, when compared with the SA group, the RA group reported significant less migraine days (RA: 5.2 ± 5.0; SA: 10.1 ± 7.1; P = 0.008), less severe migraine (RA: 2.18 ± 1.05; SA: 2.93 ± 0.61; P = 0.004), more responders (RA: 19 versus SA: 7), and increased pressure pain thresholds. No other group difference was found. Group differences were maintained at the end of the three-month follow-up, but not at the one-year follow-up. No severe adverse event was reported. Blinding was successful. Discussion. Manual acupuncture was an effective and safe treatment for short-term relief of frequent migraine in adults. Larger trials are warranted.