Fiscal rules enhance the credibility of government decisions, allow countries to have contracyclical and sustainable fiscal policies, and contribute to macroeconomic stability and economic growth.The Colombian government has applied them to limit the growth of expenditures as well as the indebtedness of subnational governments, and to promote fiscal transparency and responsibility in the public sector.However, their success has been partial, as it is evidenced by the structural nature of the central government's fiscal imbalance and the procyclicality of its policies.This paper presents and analyzes a quantitative fiscal rule of 1% of GDP in the primary surplus for the central government, in order to consolidate the country's adjustment of its public finances and shield its future fiscal policies.A contrafactual exercise shows that if the rule had been adopted at the beginning of the current decade, the central government would have obtained annual savings of nearly 0.7% of GDP between 2001 and 2006.If the rule were implemented this year, the government would attain savings of equal proportion between 2008 and 2011, which would reduce the current public debt level in about 3 percentage points of GDP by the end of the period.