The GRE Advanced Music Test and an experimental Aural Supplement (a listening test designed to measure music students'"hearing ability") were taken by 334 senior music students as part of a project conducted in 1964. The Advanced Music Test consists of 200 5-choice questions on the fundamentals of music, history and literature, theory, instrumentation and orchestration. The Aural Supplement consists of 65 questions based on brief musical examples on a 2-sided, long-playing record. The questions cover intervals, scales and modes, rhythmic patterns, 4-part harmonic progressions, cadences, nonharmonic tones, modulation, altered material, and musical forms, styles, and composers. The first phase of the project explored the relationships between the GRE Advanced Music Test and the Aural Supplement, and the second phase explored the relationship of the students' scores on both tests to their grades in appropriate undergraduate course work. Students who had taken courses in ear training, sight singing, composition, conducting, counterpoint, and class instruments scored higher than those who had not had such courses, and those who had taken composition tended to receive the highest mean scores. The students' performances on both tests were about equally related to a cumulative grade-point average in music. These and other findings indicate that the Aural Supplement seems to be a useful instrument for the measurement of "hearing ability." (WM)