Congenital amusia has been described as a lifelong deficit of music perception and production, notably including amusic individuals' difficulties to recognize a familiar tune without the aid of lyrics. The present study aimed to evaluate whether amusic individuals might have acquired long-term knowledge of familiar music, and to test for the minimal amount of acoustic information necessary to access this knowledge (if any) in amusia. Segments of familiar and unfamiliar instrumental musical pieces were presented with increasing duration (250, 500, 1000 msec etc.), and participants provided familiarity judgments for each segment. Results showed that amusic individuals succeeded in differentiating familiar from unfamiliar excerpts with as little acoustic information as did control participants (i.e., within 500 msec). The findings reveal that amusic individuals have stored musical pieces in long-term memory (LTM), and, together with other recent findings, they suggest that congenital amusia might impair conscious access to music processing rather than music processing per se.