The involvement of economic approaches is increasingly pervasive in conservation practices, from environmental policies to procedures determining the choice of conservation projects. The literature on the ethical weaknesses of economic approaches suggests to question the self-evidence of these interactions. However, economics encompasses a variety of approaches and methods, with unclear ethical underpinnings. This article contributes to these debates through a focused clarification of the ethical presuppositions of monetary valuations methods. This choice reflects that monetary valuation studies are expanding and provide numerous opportunities of interactions with conservation biologists. Identifying and understanding their ethical presuppositions is therefore pivotal for conservation biologists. For that purpose, we provide a glossary of the ethical concepts underpinning the current monetary valuation methods. We show that using a given monetary valuation method commits to endorse specific ethical stances. We then develop a practical case study: the conservation of a population of the endangered plant Leucanthemum burnatii Briq. & Cav. in a semi-natural site in the French Alps. We describe the steps that a conservation biologist could follow to decide whether she should seize opportunities to work with economists implementing monetary valuations in this setting. These stepping stones structure the approach that conservation biologists can deploy to identify the ethical stakes of conservation/economics interactions. This approach can also prove useful for conservation biologists to reflexively clarify their own ethical motivations. By appropriating this approach, conservation biologists can equip themselves to enter public debates to legitimize the usage of scientific results to improve collective decision-making on conservation issues.