This study seeks to develop and evaluate a program of selfinstructional drill materials for improving the ability of students to detect pitch errors in choral singing. The specific purposes of the study are as follows: (1) To develop and validate a visualaural test for pitch-error detection; (2) to develop a visual-aural, self-instructional program for improving the ability of students to detect pitch errors; and (3) To determine whether the program of self-instructional drill materials modifies the ability to detect pitch errors. In the first phase of this three-phase study, a body of testing materials was assembled, pilot-tested, edited, and judged reliable for use. In Phase II a body of self-instructional, programmed drill materials was assembled, pilot-tested, corrected, and judged ready for evaluation. In Phase III the procedures were as follows: (1) the subjects for whom the program was intended were administered a pretest of their pitch-error detection ability; (2) one group (A) participated in the programmed drill materials developed, while the other group (B) used no programmed materials; (3) both groups were administered a midtest to determine whether there was any change; (4) the latter group (B) participated in the programed drill materials developed, while the first group (A) no longer used the programmed materials; (5) students in both groups were administered a posttest to deterine the effectiveness of the programmed drill materials in developing the ability to detect pitch errors while reading the vocal score.