The significance of the threat of bioterrorism lies in the fear that it generates, `threat' in this context constituting not just a physical manifestation of impending danger but also a reflection of a subjective vulnerability derived from a fear of an eventuality that cannot be predicted, identified or controlled. It is a threat that plays upon our perceived biological vulnerabilities in a contemporary environment where biotechnological innovation has reconfigured European relations to biological threat and where security is increasingly informed by risk. Confronting the threat of bioterrorism in Europe, then, necessarily requires engaging with the fear associated with it. This article argues that it is by conceptualizing bioterrorism through the notion of `dread risk' that this can best be accomplished. In so doing, it elucidates the manners in which perceptions of threat interact with articulations of security to inform a cyclical threat—defence dynamic, enabling a more explicit engagement with the ways in which Europe is not only subject to biological insecurity but also a facilitator of it.