The Amazonian cosmos is a battlefield where beauty is possible but violent chaos rules. As a result, the Piaroa world is characterised by an ongoing battle between shamans who uphold, on behalf of all Piaroa, the ideal of ethical living, and forces of chaos and destruction, epitomised by malevolent spirits (märi) and dangerous sorcerers. This essay draws on ethnographic research involving shamanic apprenticeship conducted between 1999 and 2002 to explore the ethics of Piaroa shamanic practice. Given the ambivalent nature of the Amazonian shaman as healer and sorcerer, what constitutes ethical shamanic practice? How is good defined relative to the potential for social and self-harm? I argue that the Piaroa notions of ‘living by the law’ and ‘the good life of tranquillity’ amount to a theory of shamanic ethics and an ethos in the sense of a culturally entrained system of moral and emotional sensibilities. This ethos turns on the importance of guiding pro-social, cooperative and peaceful behaviour in the context of a cosmos marked by violent chaos. Shamanic ethics also pivots around the ever-present possibility that visionary power dissolves into self- and social destruction. Ethical shamanic practice is contingent on shamans turning their own mastery of the social ecology of emotions into a communitarian reality.