Through the introduction of SEA by enhancing PERS, a framework of systematic Environmental Assessment (EA), from strategic level including PPPs to the project level, has been established. Yet, despite these improvements, some continuing managerial and technical problems associated with EA implementation have been found with the recent (2006–2008) implementation of the new system. This paper reviews the overall EA system in Korea and suggests essential improvements for the current EA system based on these experiences of implementation of both EIA and SEA since June 2006. Section 2 reviews the evolution of EA in Korea and the background of SEA is presented in Section 3. Section 4 then introduces recent SEA implementation using case study analysis. Policy suggestions for the EA system are presented in Section 5.