The attentional effects triggered by emotional stimuli in humans have been substantially investigated, but little is known about the impact of affective valence on the processing of meaning. Here, we used a cross-modal priming paradigm involving visually presented adjective-noun dyads and environmental sounds of controlled affective valence to test the contributions of conceptual relatedness and emotional congruence to priming. Participants undergoing event-related potential recording indicated whether target environmental sounds were related in meaning to adjective-noun dyads presented as primes. We tested spontaneous emotional priming by manipulating the congruence between the affective valence of the adjective in the prime and that of the sound. While the N400 was significantly reduced in amplitude by both conceptual relatedness and emotional congruence, there was no interaction between the 2 factors. The same pattern of results was found when participants judged the emotional congruence between environmental sounds and adjective-noun dyads. These results support the hypothesis that conceptual and emotional processes are functionally independent regardless of the specific cognitive focus of the comprehender.