Little empirical research has been conducted on prodigies, in no small part due to the fact that there exists no agreed-upon definition with which to identify them. The most widespread definition characterizes a prodigy as a child who, at a very young age (typically before 10) performs at an adult professional level (Feldman & Goldsmith, 1986). We tested this definition by asking musicians and nonmusicians to (1) judge whether audio clips were played by a prodigy or a professional, and (2) identify which of two clips of the same piece was played by a prodigy. Listeners performed above chance in both tasks but by a very modest margin, and musicians performed better than nonmusicians. Their low performance implies that prodigies perform well enough to be judged in terms of the most demanding criteria of performance in the field. Yet older prodigies (11 to 14) were harder to distinguish from professionals than younger prodigies (under 10), suggesting a protracted developmental trajectory for prodigy performance. Furthermore, the rate at which prodigies progressed in their playing appears higher than for regular students, suggesting that rate of progress might be used as an additional criterion for defining music prodigy.