The obesity epidemic has been described as a catastrophic failure of government and public health authorities to devise and implement concerted, effective evidence-based action. To respond effectively to major public health challenges such as this, Australia needs a Ministry for the Public's Health, with a budget and accountability to parliament separate from the Health Minister. This Ministry would be better able than current health departments to develop and implement health--rather than health care--policy, to build partnerships across tiers of government, and to present the health and economic arguments for disease prevention to state and federal treasuries. Such a Ministry has international precedents, with dedicated public health agencies created in Canada, Sweden and the United Kingdom, although it is, as yet, too early to gauge their effectiveness. The Ministry would be best placed within state and territory governments, as it is at this level that partnership building and whole-of-government cooperation would have the greatest impact.