The rhinoceros is an endangered species in the world because of poaching. Unfortunately, the illegal trade in rhino horn makes current poaching activities persistent. Poaching of these rhinos is a complex issue, influenced by many factors, the most important of which is the black market price of rhino horn. Rising prices on the black market have prompted poachers to kill rhinos on a large scale, sometimes through increasingly sophisticated technologies. This article examines the potential effectiveness of legal trade as an anti-poaching measure and other alternative policies such as dehorning and patrols. Under a legal trading regime, governments and conservationists can control the horn supply and influence the market price, reducing incentives for poaching and illegal trade. We are developing and calibrating a theoretical model to explore how legal trade would affect poachers' decisions and save endangered species. We also discuss some policy implications.