Since the mid-1990s, the introduction of new public hospital payment systems to improve the efficiency of Spanish hospitals within the context of managed competition has been debated. Blended systems, which recognize the importance of the activity performed, as well as the role of the hospital in the public health system, have emerged as the best-matched tools both in risk assignment and in efficiency-economic feasibility dialectic. In this article, the payment method used in Catalonia since 1997 is analyzed and contrasted with that introduced in Andalusia in 1998. The evaluation focuses on the instruments used to incorporate the mixed model in the two different settings. On the one hand, the capacity of diagnosis related groups (DRGs) to define hospital product cost is limited. Furthermore, DRGs require numerous adjustments before introduction into Spain. On the other hand, structural level can be defined through the Grade of Memberships in Catalonia and the Basic Centers in Andalusia. We also analyze the introduction of the different methods into Spain and their adaptation to the Catalan and Andalusian environments. The transition periods seem not to have led to a definitive solution and have served to highlight the fragility of the instruments used and of the use that has been made of them. We conclude that the introduction of new tools to improve hospital efficiency through payment systems was precipitate and, to a certain extent, naive. Public hospital payment systems can be considered to be effective when they manage to allocate resources over a period of time. Ensuring the efficiency of public hospitals implies daily work on the part of each hospital and the information systems generated by regional health systems and will not be achieved through external financial tools poorly adapted to the setting in which they are applied.