The interest that countries with great natural wealth have in the reduction of external debt and the interest that industrialized countries have in the conservation of the nature can be combined by means of an exchange of external debt for nature conservation. (Debt-for-Nature Swaps [swap (from the English language): change, exchange]). Two schemes for the exchange exist: (I) Two governments, one, a creditor, interested in nature preservation and another, the indebted one, interested in reducing external debt, decide to cancel the obligation in exchange for the conservation of the nature. (II) A commercial bank of a developed country, creditor of a developing country with difficulties in the cancellation of the debt, sells in the secondary market titles of this debt by a price smaller than that of its nominal value, because only in this manner can it manage to diminish the casualty inflicted by the noncancellation of this debt. An international environmental nongovernmental organization buys the debt and negotiates with the indebted country the manner in which the debt is to be cancelled The exchanges of external debt for nature conservation represents a valuable complement to the aid for the development oriented towards the environment granted by the industrialized countries, that without a doubt must disburse the decisive contribution for the protection of the great natural wealth in developing countries.