This paper studies the efficiency of hospitals in the period 2005-2009 in Italy and Spain. The aim is to assess the dynamics of efficiency at regional level in the two countries in a comparative perspective, to investigate whether geographical differences in terms of performance diminished in the observed period. It uses a non-parametric partial frontier estimator (order-m), which overcomes some drawbacks of traditional non-parametric techniques and allows for measuring efficiency robustly with respect to outliers. We find that Italian hospitals are slightly more efficient than Spanish ones. In addition, public ownership is associated to better performance in both countries. From a dynamic perspective, results show that a process of convergence occurred in Italy that, however, did not lessen the longstanding gap between northern and southern Regions. In contrast, Spanish Comunidades Autonomas diverged in the period.