Cacao (Theobroma cacao L.) is a neotropical tree species with significant economic importance. The availability of diverse cacao germplasm is the foundation for breeding new varieties for resistance to diseases and pests, for environmental adaptation, and for superior processing quality. Cacao was domesticated in Mesoamerica several thousand years ago, but the center of diversity is in the Amazon basin in South America. There has been a significant progress in the understanding of the wild populations and related species of T. cacao in the last decade, owing to the rapid technology advance and the dedicated research programs to the conservation and improvement of cacao. This chapter examines the events that have led to the current status of conservation and utilization of wild populations and the related species of cacao.