During the last decade, nine new antiepileptic drugs were approved for use by the US Food and Drug Administration. The characteristics of three of these new antiepileptic drugs-levetiracetam, oxcarbazepine, and zonisamide-are reviewed here. Their individual characteristics, including mechanism of action, efficacy, safety, and pharmacokinetics, are compared, and their effectiveness in treating specific seizure types is noted. As with all antiepileptic drugs, the efficacy, side-effect, and pharmacokinetic profiles must be matched to each individual's clinical profile to attain the maximum benefit. All three are unique and will be useful in expanding the aggregate of therapies available to clinicians treating diverse epilepsy syndromes and seizure types. This review focuses on results in adults; pediatric experience is reported in other articles in this supplement.