Newborn screening has existed as a state-based public health service since the early 1960s. Every state and most territorial jurisdictions have comprehensive newborn screening programs in place, but in the United States a national newborn screening policy does not exist. This results in different administrative infrastructures, screening requirements, laboratory and follow-up services, medical management approaches, and related activities across the country. Federal initiatives and support have contributed to limited evaluations of various aspects of individual newborn screening programs at the national level, but funding is an issue. The national evaluation strategies have taken various forms, all with the intent of improving the screening system through review of actions taken and suggestions for future improvements. While participation in the national evaluation effort for newborn screening laboratory practices includes all US programs, and this has aided in improving quality and harmonizing protocols, other national evaluation activities have been only moderately successful. National data reporting of quality indicators for various program elements must be comprehensive and timely, and the elements must be universally accepted in order to meet the evaluation and improvement needs of the national newborn screening system. A comprehensive real time national evaluation activity will likely require additional resources and enforcement incentives. Limited federal actions through grant incentives and selected reporting requirements provide a possible means of stimulating programs to participate in national harmonization efforts. (Contains 3 tables and 1 figure.)