Recognition of the need to include economic criteria in the conservation policy decision-making process has encouraged the use of economic-valuation techniques. Nevertheless, whether it is possible to accurately assign economic values to biodiversity and if so what these values really represent is being debated. We reviewed 60 recent papers on economic valuation of biodiversity and carried out a meta-analysis of these studies to determine what factors affect willingness to pay for biodiversity conservation. We analyzed the internal variables of the contingent-valuation method (measure of benefits, vehicle of payment, elicitation format, or timing of payment) and anthropomorphic, anthropocentric and scientific factors. Funding allocation mostly favored the conservation of species with anthropomorphic and anthropocentric characteristics instead of considering scientific factors. We recommend researchers and policy makers contemplate economic valuations of biodiversity carefully, considering the inherent biases of the contingent-valuation method and the anthropomorphic and anthropocentric factors resulting from the public's attitude toward species. Because of the increasing trend of including economic considerations in conservation practices, we suggest that in the future interdisciplinary teams of ecologists, economists, and social scientists collaborate and conduct comparative analyses, such as we have done here. Use of the contingent-valuation method in biodiversity conservation policies can provide useful information about alternative conservation strategies if questionnaires are carefully constructed, respondents are sufficiently informed, and the underlying factors that influence willingness to pay are identified.