Community-based interagency collaboration may allow agencies to more effectively involve residents and create a preventive, proactive social-service delivery system. This paper presents findings of a study that investigated the role of principals in community-based interagency collaboration (CBIC) in a large midwestern city. The project was initiated by top administrators in the four participating agencies--police, social services, schools, and public health. Interviews were conducted with a total of 36 individuals--9 principals and assistant principals, 3 district administrators, 17 interagency team members, 2 parent-school liaisons, and 5 top-level agency administrators. Observations were also conducted at all interagency team meetings. Findings indicate that principals were generally supportive of the project despite their exclusion from its formative stages. The principals responded to the project implementation in four ways: (1) by ignoring the project; (2) by offering encouragement and support; (3) by interacting with neighborhood team members; and (4) by concentrating increased efforts on improving and coordinating the school's internal environment. A majority of them were unable to articulate the link between the CBIC and the schools. In contrast with the active role generally played by principals in school-based collaboration, these principals were less involved and responsible as CBIC participants. Finally, CBIC has the potential to create a sense of community, provide an outreach role for the principal, and facilitate school reform. (LMI)