The efficacy of topiramate in migraine prevention (prophylaxis) was established in two multicenter, randomized, double-blind, placebo-controlled, pivotal trials. Topiramate has received regulatory approval for use in adults for migraine prophylaxis (prevention) in the US and numerous other countries, including France, Ireland, Switzerland, Brazil, Taiwan, Spain, and Australia. Treatment with 100 or 200 mg per day of topiramate was associated with significant reductions in the frequency of migraine headaches, number of migraine days, and use of acute medications. No increase in efficacy was observed between 100 and 200 mg per day of topiramate. Based on efficacy and tolerability, 100 mg per day of topiramate should be the initial target dose for most patients. The most common adverse events were paresthesia, fatigue, decreased appetite, nausea, diarrhea, weight decrease, and taste perversion. Topiramate is a first-line migraine preventive drug and should especially be considered as a preferred treatment for all patients who are concerned about gaining weight, who are currently overweight, or who have coexisting epilepsy.