In November, 1997, The Institute of Medicine convened a one-day conference to explore areas for potential collaboration to improve quality among competing health plans consistent with antitrust and other legal requirements. The conference was convened to clarify the limits of such potential activities and to explore ways to stimulate collaboration; in short, to explore permissible and promising areas for collaboration for competing health plans. Competition has existed at the provider level in the pre-managed care era and continues among physicians, physician groups and hospitals today. What is new is the extent of competition at the managed care organization level in individual regional markets. As large numbers of individuals are enrolled in health plans, the potential for new forms of cooperation for improving quality of care becomes possible. Along with these new possibilities, however, come questions about whether they bring the potential for antitrust violation.