Migraine, being disabling and common, is a costly illness. The bearers of the cost are a broader band of society than the sufferers from the disease, and the elements of the cost are not only monetary. Treatment of migraine has the potential for reducing this cost but carries a cost of its own. In the balance between these, those who pay are not necessarily the same as those who gain. Various forms of analysis are employed in relating illness costs at individual and societal levels with those of measures intended to contain them. Questions that arise are whether costs are saved overall by treatment, and which of different treatment options give greater savings. In the absence of much data, there is heavy dependence on assumptions in attempts to answer these questions. A full analysis should take into account the extent to which the availability of new and very effective treatments might alter demand and clinical practice, and also the impacts of ineffective use and inappropriate use of treatments.