We report a small open pilot study to evaluate the efficacy of lamotrigine (100 mg/day) in the prevention of migraine with aura attacks. We studied 24 patients affected by migraine with aura with a high frequency of attacks. Following a 1-month run-in period, the patients took lamotrigine for 3 months. Mean attack number per month was reduced from 6.1 +/- 4.1 during the run-in period to 0.7 +/- 1.3 at the 3rd month of treatment (p < 0.0001). In 13 out of 21 patients who completed the study, the attacks were completely abolished at the 3rd month of treatment, while only one patient was completely unresponsive to the drug. Lamotrigine seems worthy of a controlled trial as prophylaxis of a migraine with aura.