A product native to the Amazon forest, cacao became the most important staple of the Portuguese Amazonian colonial economy from the late seventeenth until the mid-nineteenth century. Based on extensive research in Brazilian and European archives, this article analyses cacao exploitation in Portuguese Amazonia, examining its dual spatial dimension: the expansion of an agricultural frontier, and the expansion of an extractive frontier in the deep hinterland, with a particular focus on the role that Indian labour played in this development.