Behavior modification is discussed as a new approach to teaching and curriculum implementation in physical education. It is suggested that behavior modification offers physical education several advantages: (1) extensive research findings of various kinds directly applicable to the work of the physical education teacher; (2) a set of behavioral principles and applied experimental procedures that can be used to help implement and evaluate physical education curricula and improve many motor, athletic, health, and social behaviors of concern to the physical education teacher; and (3) relevant, objective, accountable, effective, and positive teaching, evaluation, and record-keeping. Specific topics covered include: educational analysis of teaching principles and procedures; the behavior modification approach; behavior improvement; the methodology of behavior modification approaches; change procedures; and the future of behavior modification in physical education. Selected research references are listed. (MM)