With its more than 35 years of experience with EIA of NEPA in United States, the extensive knowledge base of EIA could be the most suitable place for initial field of HIA to explore lessons available for. However, caution is needed as the technical differences in analysis, different policy context, and distinct professional culture between EIA and HIA might be. The successe of EIA of NEPA is the integration of environmental goals into decision making process, improved planning, and increased transparency and public involvement, whereas shortcomings of it were defined as the excessive volume and complexity of EIA documents, the limited and adversarial public involvement, the procedural process (not substantive), focus on projects (not on policies and programs), and the limited consideration of health impacts. Integrating HIA into existing EIA process is positive in two reasons that the human health is closely related with natural environment and EIA process is a fully established process that effectively cuts across bureaucratic and sectoral boundaries. Also, integrating of HIA into EIA might be a way with least resistance for the widespread use. A freestanding HIA separated from EIA is desirable in terms of excessive volume of EIA documents and the procedural and legal focus of EIA. It is needed to develop the formulated methodologies for advancing HIA whether it is a part of or separated from EIA, and to estimate the potential values of HIA in the substantial society context. When possible, HIA should be established on the ways that EIAs have been used successfully.