This paper reviews the key issues and methodologies involved in the replication of social programs, as they pertain to non-profit sector development in the United States and in international development. The related process of knowledge transfer and dissemination, as well as the more specific strategies involved in replication and going-to-scale are examined. Strategies discussed include the franchise approach, mandated replication, staged replication, concept replication, and spontaneous replication. The universalist and contextualist approaches are also discussed. A principal argument of the paper is that there are few effective and sustainable programs reaching out to large numbers, and that these are difficult to establish. The progress of replication efforts is often measured in terms of criteria such as the effect on participants, the numbers reached, the spread of project sites over a region, or the volume of services extended. Advances are seldom gauged against overall needs in a given country or region; the result is that program impact is often localized and may not significantly affect the total target population. Politicians, researchers, donors and policymakers are advised to use caution in evaluating proposals, as not all of them consider the broader impact of the program. (JPB)