Biodiversity and species conservation are among the most urgent global issues. Both are under serious threat because of human intrusion and as a result, it is likely that present and future projects will affect threatened and endangered species. Thus, it is important to account for these impacts when evaluating and conducting cost and benefit analyses of projects. Due to their public good character and non-tradability, the total economic value of threatened and endangered species cannot be reflected by a market price and therefore, alternative approaches (stated preference method) are needed to determine their monetary value. This paper reviews and compares the valuation literature on threatened and endangered animals and conducts a meta-analysis regression to identify explanatory variables for the variation in willingness to pay for threatened and endangered species. The main findings of the meta-analysis show that the interaction of the level of threat and charisma have a positive effect on willingness to pay. Furthermore, developed countries have a higher willingness to pay compared to developing countries. Similarly, visitors of conservation sites have higher willingness to pay than residents. The provided example of a benefit transfer of the estimated function shows the practicability of our results.