Two children developed severe cognitive and behavioral deterioration suggestive of a degenerative disease while being treated with sodium valproate for idiopathic, localization-related epilepsy with centrotemporal spikes. Magnetic resonance imaging revealed marked central and generalized cortical and cerebellar atrophy. In both patients, clinical symptoms and signs cleared in a few weeks following valproate withdrawal. The magnetic resonance imaging appearance improved within 3 months in 1 of the patients and normalized in both after 6 and 12 months. No metabolic changes were associated with the clinical or imaging abnormalities. Although the mechanism of this rare idiosyncratic complication of valproate therapy is unknown, we advocate discontinuing valproate therapy in all epileptic patients with neuromental deterioration or brain atrophy of unknown etiology.