Since passage of the National Environmental Policy Act of 1969, power plant siting procedures have undergone extensive change. The “environmental assessment matrix” was developed for use as an active tool in an ongoing nuclear power plant siting study. Its use is not intended to eliminate engineering judgment and ingenuity from the plant siting process, but rather to document the procedures used and conclusions drawn. When used in an iterative manner during a site-selection study, the environmental assess ment matrix provides valuable insight into a complex evaluation problem, documentation of the logic used, and a graphic display that can be used for presentation at open meetings.