The Interdisciplinary Generalist Curriculum (IGC) Project significantly advanced collaboration in the development of medical school curricula. As primary care faculty began to work together they encountered and overcame many challenges inherent in this new process. Inclusion of other faculty and departments, as well as dedicated support from the deans' offices, became necessary to the success of the projects. The continuation of successful collaborative projects in the medical school environment requires a common commitment of faculty, students, department chairs, and the dean's office; protected time; and involvement of faculty from other disciplines. This article outlines initial models of collaboration implemented in the IGC Project, followed by a description of the expected and unexpected outcomes of these collaborative efforts, and a discussion of the emergence of new ways of collaborating, with recommendations for successful collaborative efforts.