The neotropics harbor an enormous biological diversity, including the largest tropical rainforest in the world and some of the major hotspots for biodiversity conservation. Such environments have a long history of interaction with various human communities that have intensively used their genetic resources. Therefore, it must not be surprising that some of the most important centers of plant domestication are in the neotropics. There are many crops of local and global importance among the plants domesticated in the neotropics, and the diversity of their wild relatives is also high. This highlights the importance of the conservation of the native biomes along with their associated people and useful plant species. In situ preservation (or conservation) consists of maintaining the species in their habitats, enabling them to keep evolving within their environments. Alternatively, ex situ conservation consists of maintaining species outside their native environment under human care, which in principle, enables that their genetic resources are readily available for use. Both of them may be implemented by different means, such as in vitro conservation, an ex situ strategy that consists of keeping biological parts of species within test tubes in the laboratory. Population genetic studies are important sources of information for many applications, as discussed throughout this book. The aim of this chapter is to discuss how population genetics can be useful to assist the various conservation strategies aimed at plants of the neotropics.