The research defines the fiscal behavior of the autonomous regions over recent years, to determine whether the different structural characteristics between the autonomous regions is manifested in varied patterns of behavior. To carry out this work, the study constructs a theoretical model that analyzes the factors that explain public expenditure and are also responsible for its growth, as well as the effect of fiscal co-responsibility on this expenditure. Among the conclusions extracted from the research are that the wealthiest regions appear to be unsatisfied with the current level of expenses and that debt issuance has fostered excessive growth in public expenditure.