Objectives: Recent studies with event-related brain potentials (ERPs) investigating music processing found (early) negativities with righthemispheric predominance as a response to inappropriate harmonies within sequences of chords. The stimuli used in those studies were fairly artificial in order to control the experimental factors (e.g. variations in tempo and loudness were eliminated). This raises the question of whether these ERPs can also be elicited during listening to more naturalistic stimuli.Methods: Excerpts from classical piano sonatas were taken from commercial CDs and presented to the participants while recording the continuous electroencephalogram. Expected chords and unexpected (transposed) chords were presented at the end of chord-sequences.Results: Unexpected chords elicited a negativity which was maximal around 250 ms, visible over both hemispheres, and preponderant over right temporal leads.Conclusions: The found negativity is strongly reminiscent to both early right anterior negativity and right anterior-temporal negativity, suggesting that cognitive processes underlying these ERP components are not only elicited with fairly artificial experimental stimuli but also when listening to expressive music. q