We report the case of a patient presenting with recurrent transient dyscognitive episodes and memory disturbances, simulating the clinical picture of early Alzheimer's disease (AD). Neuropsychological examination showed only episodic memory impairment without significant progression over time in the absence of any other cognitive dysfunctions; magnetic resonance imaging failed to show selective temporal atrophy. The suspicion that a nocturnal epileptic seizure had occurred arose on the basis of a clinical report of tongue biting and the findings of sharp waves over the temporal region on standard EEG. Thus 600 mg/day of carbamazepine was added to donezepil therapy. Antiepileptic treatment completely reversed the cognitive disturbances. Our observation stresses the possibility that unrecognised epilepsy may present as early AD.