The aim of this paper is analyze the causes of fiscal slippage at the regional level in Spain during the period 2005-2015. According to results, the main factors are the deficit deviation of past year, the variation in the deficit target, total revenues provided by the regional financing system, the existence of changes of government and, to a lesser extent, political affinity between incumbents at both central and regional levels. On the contrary, spending increases in the past, the debt burden interest and the electoral cycle are not significant variables.