The intent of this thesis was to examine the nature and function of instrumental warm-up in the secondary music classroom. The instrumental warm-up is an important structural component of the secondary instrumental music rehearsal. It occurs at the beginning of each rehearsal and provides an excellent opportunity to engage students in musical problem solving activities. The cognitive entry behaviors of students account for a significant portion of the total achievements in any learning episode. Therefore, the development and implementation of the instrumental warm-up has a significant effect on the success of each rehearsal. This study identifies the components of the instrumental warm-up and examines the activation of physical and mental systems necessary to play a musical instrument. Special attention is given to the development of a positive self image in students and the implementation of goal-oriented thought in the secondary music classroom. The teaching of musical concepts and expansion of melodic and rhythmic vocabularies are also discussed. The examination of the nature and function of the instrumental warm-up has led to several important conclusions regarding the pedagogy used by music educators to facilitate this part of the secondary music rehearsal.