On Sep 27, 2011, Article 135 of the Spanish Constitution was amended for the purpose of introducing deficit and debt rules. The reform, announced just a month earlier by then Prime Minister Jos Luis Rodrguez Zapatero, was adopted following a special procedure established in Article 167 of the Spanish Constitution,1 and was a speedy reaction to the unsustainably high cost of Spanish bond yields, which had climbed to a 7% interest rate during Aug 2011. This constitutional reform was primarily intended to appease financial markets and instill credibility in the Spanish economic system. This article discusses the Spanish legal framework for curbing the public debt and the deficit.