Changing Problem Behavior is a manual for managing behavior change projects from the functional assessment of problem behaviors, through constructing and implementing a behavior change program and transitioning to the ongoing maintenance of changes. It utilizes a behavior analytic approach with a strong emphasis on positive reinforcement based methods and avoidance of aversive methods. It presents a systematic and natural science based approach to managing problem behavior cases for professional animal behavior technologists. The strategies and procedures are applicable to all species.