This article describes the results of a study on interagency collaboration required to make major systemic changes in order to address the needs of emotionally and behaviorally disturbed youth. Interviews were conducted with practitioners from a cross-section of agencies that worked with high-risk gang youth. The intent was to examine both the interpersonal and structural factors that either promoted or impeded the collaborative process. Of the factors contributing to successful collaboration, communication and cooperation were frequently cited as critical elements. Five interactional patterns were cited as contributing to negative collaboration, such as diffusion of responsibility, blaming other agencies for the failures of youth, withholding information between agencies, agencies "covering up" mistakes made in assessment or treatment, and prematurely terminating collaborative arrangements. "Agency fear" was proposed as a primary construct responsible for collaborative behaviors that influence both the coordination of treatment programs and the clinical behaviors of practitioners. (LC)