Recent international initiatives for disease control suggest that, in the future, the consequences for trade of an exotic disease outbreak may not be as severe as estimated in the past. If zoning were to be accepted by Australia's trading partners, then the major effects may be felt at the regional rather than the national level. A study, using an integrated epidemiological/economic model, was undertaken to compare the impacts of 3 important exotic diseases (foot-and-mouth disease, classical swine fever and sheep pox) in 3 different regions of Australia. The study demonstrated that there are significant differences between the size and effect of different disease outbreaks. Regional factors influence not only the way that the disease will spread and manifest itself, but also the effects on local communities. Foot-and-mouth disease caused more economic losses than sheep pox or classical swine fever. The major determinant of differences in the effects of the diseases between regions was the nature of the regional economies. The less diversified the economy, the greater the effect of an exotic disease outbreak in relation to the size of that economy.