Continuing medical education's transition from an emphasis on dissemination to changing clinical practice has made it increasingly necessary for CME providers to develop effective interorganizational collaborations. Although interorganizational collaboration has become commonplace in most sectors of government, business, and academia, our review of the literature and experience as practitioners and researchers suggest that the practice is less widespread in the CME field. The absence of a rich scholarly literature on establishing and maintaining interorganizational collaborations to provide continuing education to health professionals means there is little information about how guidelines and principles for effective collaboration developed in other fields might apply to continuing professional development in health care and few models of successful collaboration. The purpose of this article is to address this gap by describing a successful interorganizational CME collaboration—Cease Smoking Today (CS2day)—and summarizing what was learned from the experience, extending our knowledge by exploring and illustrating points of connection between our experience and the existing literature on successful interorganizational collaboration. In this article, we describe the collaboration and the clinical need it was organized to address, and review the evidence that led us to conclude the collaboration was successful. We then discuss, in the context of the literature on effective interorganizational collaboration, several factors we believe were major contributors to success. The CS2day collaboration provides an example of how guidelines for collaboration developed in various contexts apply to continuing medical education and a case example providing insight into the pathways that lead to a collaboration's success.