This experiment was intended to explore the effects of the emotional connotation of stimuli on the hemispheric lateralization. Ten right-handed male subjects (Ss) were presented a set of slides of faces expressing a positive emotion, a negative emotion or emotional neutrality. The ERPs elicited by the face stimuli were recorded from 16 leads and topographic maps of P3 amplitude were created. The results show that when Ss had to discriminate between emotional (target) and neutral (non-target) faces, the main differences were seen predominantly over the right centroparietal area. On the contrary, when Ss had to detect a face particularity not related to the emotional content, the differences between target and non-target faces were bilaterally distributed. The present results support the hypothesis that the perception of emotional expressions is processed mainly by the right hemisphere.