While the importance of nursing best practice champions has been widely promoted in the diffusion of evidence-based practice, there has been little research about their role. By learning more about what champions do in guideline diffusion, the nursing profession can more proactively manage and facilitate the role of champions while capitalizing on their potential to be effective leaders of the health care system. To determine how nursing best practice champions influence the diffusion of Best Practice Guideline recommendations. A mixed method sequential triangulation design was used involving two phases: (1) key informant interviews with 23 champions between February and July 2006 and (2) a survey of champions (N= 191) and administrators (N= 41) from September to October 2007. Qualitative findings informed the development of surveys and were used in interpreting quantitative information collected in phase 2. Most interview and survey participants were female, employed full-time, and had worked in practice for over 20 years. Qualitative and quantitative findings suggest that champions influence the use of Best Practice Guideline recommendations most readily through: (1) dissemination of information about clinical practice guidelines, specifically through education and mentoring; (2) being persuasive practice leaders at interdisciplinary committees; and (3) tailoring the guideline implementation strategies to the organizational context. Our research suggests that nursing best practice champions have a multidimensional role that is well suited to navigating the complexities of a dynamic health system to create positive change. Understanding of this role can help service organizations and the nursing profession more fully capitalize on the potential of champions to influence and implement evidence-based practices to advance positive patient, organizational, and system outcomes. ©2010 Sigma Theta Tau International.