Event-related potentials (ERP) were recorded in two experiments to examine the effects of concreteness and emotionality on visual word processing. Concrete and abstract words of negative, neutral or positive valence, as well as pseudowords were presented in a hemifield lexical decision task. Experiment 1 yielded early (P2) and late (N400, late positive component/LPC) emotional word effects. Concreteness affected the N400 and the LPC. In line with the extended dual coding model and with previous studies, the N400 effect represents greater semantic activation, whereas the LPC effect may result from mental imagery being activated by concrete words. Experiment 2 engaged participants in a go/no-go task pressing a button for pseudowords. Here, emotionality and concreteness modulated the N400 independently, but interacted in the LPC time window. Only concrete emotional words differed in the LPC response suggesting that concrete negative words such as "wound" or "bomb" differ from neutral and positive words as a function of mental imagery.