We investigated the effect of long-term musical training on the time course of development of neuronal representations within the auditory cortex by means of magnetoencephalography. In musicians but not in nonmusicians, pre-attentive encoding of a complex regularity within a tone sequence was evident by a constant increase of the pattern mismatch negativity within < 10 min. The group difference was more pronounced in the left hemisphere, indicating stronger plastic changes in its structures supporting temporal analysis and sound pattern encoding. The results suggest an effect of long-term musical training on short-term auditory learning processes. This has implications not only for cognitive neuroscience in showing how short-term and long-term neuronal plasticity can interact within the auditory cortex, but also for educational and clinical applications of implicit auditory learning where beneficial effects of (musical) experience might be exploited.