Over the last decade, many governments around the world have embraced the concept of the bioeconomy and its promise to provide a new engine of growth and deliver significant health and environmental benefits in the future. Drawing on ideas from the sociology of science and economic sociology, and focusing on the biomedical technology sector, this article examines the sociopolitical significance of the promissory discourse of the bioeconomy. We argue that this discourse plays a crucial performative role in contemporary biopolitics, in mobilising actor networks, attracting venture capital and research funding, and shaping the possibilities for action. However, for reasons that we outline and as the Australian experience in the biotechnology sector illustrates, the performativity of the bioeconomy is prone to failure. The article concludes by considering the implications of promissory discourse for anticipatory governance in relation to science and for scientific practice.