In this paper a method is developed to derive prices for natural goods from information about material and energy flows within ecosystems. The derivation is based on an analogy between ecological and economic systems : both systems are characterized by flows of material and energy. To derive ecosystem prices the mathematical struc2 ture of Koopman’s economic linear production model is applied. The ecological interpretation of these prices is dis2 cussed and the uniqueness of the price system is investigated. An algorithmfor price calculation is derived and dem2 onstrated with a numerical example.