Since the late 1980s, the concept of precaution has been incorporated into numerous international agreements and laws, as well as in domestic statutes and policies in many countries. This paper examines the international emergence of the concept and its application in Australia. Despite rapid growth in adoption of the so-called ‘precautionary principle’, the concept remains highly controversial, and its success in terms of improving environmental and natural resource management has been questioned. A common misconception is that the principle prescribes action. In fact, internationally accepted definitions are about decision-making processes. This paper argues that implementation guidelines are essential to ensure that precautionary decision-making is consistent with good decision-making principles, and to avoid unnecessary costs and perverse outcomes.