Objective: Studies with endogenous event related potentials, demonstrated that musical training influenced auditory brain functions. The aim of the present study was to investigate whether auditory event related potentials (ERPs)-mismatch negativity (MMN) and P300-differ between musically trained and musically lay subjects. Material and Methods: MMN and P300 were recorded in 19 musically trained (mean age 20.2 +/- 2.38 years) and in 17 musically lay subjects (20.76 +/- 1.75 years) using an "oddball paradigm". 20% of stimuli were rare (target) tones of 2000 Hz, whereas the remainder was frequent (non-target) tones of 1000 Hz. Subjects were instructed to press a button when they encountered the rare stimuli. Latencies and amplitudes of auditory MMN and P300 responses obtained from musically trained subjects were compared to those obtained from musically lay subjects. Results: In musically trained subjects, MMN latencies were significantly decreased while MMN amplitudes did not differ between the 2 groups. P300 latencies and amplitudes did not differ between musically trained and musically lay subjects. Conclusion: Decreased latencies of MMN in musically trained subjects suggest that musical training might influence pre-attentive auditory processing and auditory sensory memory mechanisms can be modulated by musical experience. It is possible that electrophysiological responses obtained from musicians reflect structural adaptations in response to long term music training.