Economic costs are relevant to endangered species protection in both theory and practice. Recovering endangered Snake River salmon will require modifying public land use, restricting fishing and hatchery production, reducing water for agriculture, and altering the operation of hydroelectric dams. The economic costs are estimated to range from $246 million to $359 million per year. While the estimated cost is not matched by the estimated increased value of fishing, the nonuse value of salmon recovery may be very large. Better economic and biological information is needed to assure that decisions for salmon species protection are reasonably cost effective. (JEL Q28, H43)