The mitigation system, as it has been practiced in the United States over the past 20 some years, has not only contributed to enhancing and restoring habitats, but also to advancing our understanding of the ecosystem by leaps and bounds. It also engendered society's perception of the need for environmentally friendly lifestyle. All these gains owe, to a large extent, to the controversial section 404 clause in the Clean Water Act which imposes 'compensatory' mitigation on 'unfriendly' development activities. The mitigation system is here to stay, provided that it will continue to evolve toward eco-realism, eventually to become part of the sustainable lifestyle. The system in the years to come is envisioned to emphasize watershed-wide plaming, market forces in the form of mitigation banking and trust funds, among others, risk justification, economic impacts, easing of regulatory control, biodiversity, and performance monitoring of man-enhanced habitats.