Affective stimuli encountered in everyday life - such as emotional words, scenes or facial expressions - can elicit well-investigated emotional experiences. For instance, two distinct event-related brain potentials (ERPs) have been reported in response to emotional facial expressions, an early posterior negativity (EPN), associated with enhanced attention and perception of affective stimuli, and a later centro-parietal positivity (LPP), assumed to reflect processing of the intrinsic relevance of emotional stimuli. Other rich sources of emotions that have yet received little attention in EEG research are internal mental events such as thoughts, memories and imagination. Here we investigated mental imagery of emotional facial expressions and its time course using ERPs. We presented participants with neutral faces and asked them to imagine the faces with an emotional or neutral expression. Early ERP modulations during imagery resemble the effects frequently reported for emotional facial expressions, suggesting shared early processes underlying emotion perception and imagination.