The objective of this paper is to analyze the role of fiscal policy sustainability over the determinants of domestic interest rate of a group of 23 emerging market countries in the period 1996-2008. Among the analyzed countries are: South Africa, Argentina, Brazil,Bulgaria, Chile, China, Colombia, Egypt, Ecuador, Philippines, Hungry, India, Indonesia,Kazakhstan, Malaysia, Mexico, Peru, Poland, Russia, Thailand, Turkey, Ukraine and Venezuela. We have used several domestic interest rates from two databases: 1) IFS:Government Bond Yield, Deposit Rate, Discount Rate/BankRate, Treasury Bill Rate, Money Market Rate; and 2) JPMorgan (2006): yield of JPMorgan Government Bond Index- Emerging Markets. Fiscal policy sustainability was based on Fávero and Giavazzi (2004), and known as the accumulation of primary budget surplus, that keeps the debt-to-gdp ratio constant. The main result shows that is not possible to reject the hypothesis that fiscal policy sustainability determines the level of domestic interest rate and the effect has the expected signal, i.e., an increase in 1% on the accumulation of primary budget surplus reduces the domestic interest rate by roughly 100 basis point, a coherent figure with studies focusing on emerging market countries.