Zonisamide, a newer antiepileptic drug (AED) with multiple mechanisms of action, has been increasingly used in patients with generalized epilepsies. This case study focuses on the effects of zonisamide on the EEG of a patient with juvenile myoclonic epilepsy. The patient had complete resolution of myoclonic jerks and absence and generalized seizures on introduction and titration of therapy with zonisamide; his EEG showed almost complete resolution of generalized spike and wave discharges and electrographic absence seizures. This case report suggests that zonisamide may be effective in the treatment of medication-resistant idiopathic generalized epilepsy and that it may lead to a significant improvement of the EEG. © 2004 Elsevier Inc. All rights reserved.