We evaluate how the productive structure and level of specialization of a hospital affect technical efficiency by analyzing a six-year panel database (2000/2005) drawn from hospital discharge records and Ministry of Health data. We adopt a distance function approach, while measuring the technical efficiency level with stochastic frontier techniques. After controlling for environmental variables and hospital case-mix, inefficiency is negatively associated with specialization and positively associated with capitalization. Capitalization is typical of private structures which, on average, use resources less efficiently with respect to public and not-for-profit hospitals. Finally, by looking at scale elasticities, we find some evidence of unexploited economies of scale, leaving room for centralization.