This paper offers an analysis of the costs and the financing of HIV/AIDS programs for countries in sub-Saharan Africa. The rate of external financing varies with gross domestic product (GDP) per capita, but not much at all with HIV prevalence. In six of the thirty-four countries examined, the costs of HIV/AIDS programs will exceed 3 percent of GDP by 2015. Most of these are low-income countries. Considerable external support at current rates in these countries would help contain the fiscal costs to around 1 percent of GDP. But if that support dwindles, countries would have to borrow money or cut back on their own spending for HIV/AIDS.