The consolidation of a universal health system coupled with a process of regional devolution characterise the institutional reforms of the National Health System (NHS) in Spain in the last two decades. However, scarce empirical evidence has been reported on the effects of both changes in health inputs, outputs and outcomes, both at the country and at the regional level. This paper examines the empirical evidence on regional diversity, efficiency and inequality of these changes in the Spanish NHS using cross-correlation, panel data and expenditure decomposition analysis. Results suggest that besides significant heterogeneity, once we take into account region-specific needs there is evidence of efficiency improvements whilst inequalities in inputs and outcomes, although more 'visible', do not appear to have increased in the last decade. Therefore, the devolution process in the Spanish Health System offers an interesting case for the experimentation of health reforms related to regional diversity but compatible with the nature of a public NHS, with no sizeable regional inequalities.