Our results indicate that health system resource gaps for responding to a mild to moderate pandemic influenza scenario are wide and vary greatly, both within and between countries in Southeast Asia, and that these gaps could have a profound impact on pandemic-associated mortalities. Our estimates of resource gaps and avoidable mortality rates at country level show a clear association with national GDP. This result is consistent with a previous analysis of data from the 1918 influenza pandemic, which found that per capita income explained a large proportion of the variation in mortality across countries during the pandemic period [14] . Moreover, extrapolation of these mortality rates to the 2004 world population suggested that around 96% of deaths from pandemic influenza would occur in developing countries [14] . Our results suggest that, due to inequitable distribution of resources, the variation in pandemic burden is likely to be profound within, as well as between, countries. Countries which have experienced the highest burden of Highly Pathogenic Avian Influenza (H5N1), namely Vietnam and Indonesia, appear to be most prepared in terms of the availability and geographical distribution of oseltamivir. In the other study countries, we estimated that central stockpiles of oseltamivir would be sufficient to cover any provincial gaps for treating all severe cases from the modeled scenario, and thus mobilization of this resource could potentially avert a large number of avoidable mortalities in these countries. Indeed, in all countries except Vietnam, we estimated that optimum mobilization of resources across administrative boundaries could save more than 10% of avoidable deaths. While timely mobilization of resources may be possible in Taiwan, with its small geographical size and relatively developed infrastructure, the feasibility of this scenario is questionable in the poorer, and larger, countries of the Mekong region, where it might be prudent to disburse central stockpiles of antiviral drugs to provincial and district health facilities prior to an outbreak.