A lack of information on environmental protection values, especially non-market values, has contributed to wetland degradation in the Mekong River Delta. To fill this information gap, this study uses choice modelling to estimate the biodiversity protection values of Tram Chim National Park, a typical wetland ecosystem of the Delta. The estimated net social benefit of a proposed protection program ranges from USD0.52 million to USD1.84 million. This suggests that the program's implementation would improve social welfare. Some choice modelling issues, including the use of focus groups, aspects of questionnaire designs, and different survey modes, are discussed in the context of a developing country application.