Environmental impact assessment <EIA> procedures have been adopted in major countries of the Asia and the Pacific Regin. This paper reviews the background of EIA development, similarity and difference of various EIA procedures, and accumulation of EIA experiences in the region. It also reviews EIA methodologies applied in the region and analyses the constraints of EIA implementation in the region. As a result of this analysis, it suggests the urgent development of rapid EIA techniques, environmental informatin systems, and manpower development trainings.