This article addresses health behavior change program fidelity using the five components of fidelity from the National Institute of Aging’s Behavior Change Consortia: fidelity in design, training, delivery, receipt, and enactment. Fidelity is a key issue in successful translational research projects into community settings. The authors examine four programs sponsored by the Administration on Aging that target health behavior change in physical activity (EnhanceFitness), chronic disease self-management (Partners on the PATH [Personal Action Toward Health]), fear of falling and falls prevention (Matter of Balance), and depression management (Healthy IDEAS). This article (a) describes the tools and strategies used by these projects to track and enhance fidelity to the core elements of the original intervention studies, (b) compares and contrasts each project’s mechanisms of fidelity, (c) provides examples of fidelity outcomes, and (d) discusses themes and lessons learned that may be useful to others in developing the “next generation” of program translation.