Cognitive event-related potentials (ERPs) were measured during a timbre discrimination task from three subject groups varying in musical experience. The P3 component of the ERP was recorded from musicians with absolute pitch, musicians without absolute pitch, and nonmusicians during a task comprising timbres of varying difficulty. The three-timbre series, all of which consisted of the same pitch, were (1) string instruments in the same family (cello and viola), (2) flutes made of different materials (silver and wood), and (3) instruments of slightly different size (B-flat versus F tubas). The amplitude and latency of the P3 component varied systematically as a function of musical experience and type of timbre discrimination. The difficult timbre task resulted in mean P3 amplitudes which were larger for musicians relative to nonmusicians, however P3 amplitudes were similar for the two additional timbre series. The mean P3 latencies for musicians were shorter when compared to nonmusicians across all three series. In comparison, the AP subjects displayed the shortest mean P3 latencies, but had smaller P3 amplitudes relative to both musicians and nonmusicians. The implications of these findings suggest that perceptual tasks involving one of the fundamental building blocks of music, namely timbre, does elicit differential brain activity from memory or information processing systems from subjects with varying degrees of musical training.