This article considers another group of educators involved with the adoption of model-based instruction (MBI)--the cooperating teachers, who supervise physical education teacher education (PETE) student teachers in the Georgia State University (GSU) program. The university spends several semesters educating preservice teachers about the skills and knowledge necessary to become effective teachers with MBI. The student teacher is then assigned to a cooperating teacher to practice this new knowledge and implement theories into real-world practice. Cooperating teachers can reinforce the lessons learned at the university or cause a "washout" effect (Zeichner & Tabachnick, 1981). Because of the key role that cooperating teachers play in the educational process, the purpose of this study is to examine the factors that influence cooperating teachers' decisions to adopt MBI. (Contains 2 figures and 2 tables.)