Pitch identification by absolute-pitch (AP) possessors was tested with three different timbres. Twelve notes per octave in the equally tempered chromatic scale were presented randomly over a seven-octave range. AP subjects identified the note quite accurately but showed a considerable number of octave errors, indicating that they indeed responded primarily to pitch classes. By contrast, subjects lacking AP gave widely scattered responses, indicating that they could not perceive pitch classes at all but responded solely on the basis of the approximate pitch region (pitch height). The performance of AP subjects was best for piano tones and worst for pure tones, and responses were most accurate in the middle region of the musical pitch range. Of 12 pitch classes, white-key notes on a musical keyboard (diatonic tones in the C major scale) tended to be identified more correctly and rapidly than were black-key notes (nondiatonic tones in the C major scale). All of the AP subjects had received training on the piano since a young age. It is suggested that AP can be acquired through such early musical experience.