Ebselen is a seleno-compound used in the treatment of neurological disorders involving the glutamatergic system. Although ebselen is currently used in clinical trials, the physiological effects of this seleno-compound are poorly known. In this study, we investigated the effects of intrahippocampal infusion of ebselen (0.1-3 nmol) in rats submitted to an inhibitory avoidance task. Ebselen (1-3 nmol) infused after the training session impaired retention of inhibitory avoidance, tested 90 min or 24 h after the training session. Moreover, ebselen also impaired the retention when infused 30 min prior to training or 10 min prior to test sessions. In summary, ebselen impaired memory consolidation, acquisition and retrieval. This amnesic effect of ebselen could be related to oxidant activity at N-methyl-D-aspartate (NMDA) receptors. Our results indicate that more studies must be performed to investigate the mechanisms of this amnesic effect and whether ebselen has a cognition-impairing effect when administered chronically.