The object of this study is the environmental park “Chico Mendes” located in Rio Branco - Acre. Being unique and all-enclosing in its nature it is a public asset. The contingent valuation makes possible the determination of the total economic value total of a public asset. The people’s willingness to pay for the park maintenance and conservation shows a determination of the consumers’ preference. This work attempts to determine the total economic value of the park. The results show that family income, value of monthly contribution, sex and age explain the probability of a person to contribute to the park conservation. Finally, bootstrapping and risk analysis provide greater safety to the results found.