The next influenza pandemic could cause illness and death on a large scale, over a wide area, in a short space of time. Such a prospect arguably sets this disease apart from those regarded simply as health issues, and some Western governments have started framing pandemic influenza as a threat to national security. The benefit of this could be the improvement and mobilisation of public health resources. However, the framing of a health issue in security terms could also lead to emergency responses which are ineffective, counterproductive and/or unjust. In particular, if too much emphasis is placed on the health and security interests of individual states, this might detract from the international cooperation necessary to resist pandemic influenza effectively in the long term.