This article follows a conceptual article published in this journal by Elliott et al. and provides an empirical evaluation of the Canadian Heart Health Initiative—Dissemination Phase. Between 1994 and 2005, seven provincial research teams of the Canadian Heart Health Initiative—Dissemination Phase undertook projects to disseminate and evaluate the uptake of evidence-based chronic disease prevention strategies in their respective health systems. In this study, the authors draw from document and stakeholder interview analyses to assess the influence of strategic decisions about dissemination objects, targets, activities, and relationships between knowledge producers and users on the outcomes of chronic disease prevention programming. The findings show that successful dissemination strategies are not necessarily contingent on a high level of fidelity across these dimensions but depend more on the extent to which they are responsive to contextual variables within highly dynamic health systems.