In this paper we attempt to identify behavioral differences between public and private not-for-profit hospitals, by exploiting the introduction of the DRG-based payment system in the Italian NHS during the second half of the 1990s. We estimate the technical efficiency of a sample of hospitals for the period 1995–2000 considering an output distance function, and adopting both parametric (COLS and SF) and nonparametric (DEA) approaches. Our results show a convergence of mean efficiency scores between not-for-profit and public hospitals, and seem to suggest that differences in economic performances between competing ownership forms are more the result of the institutional settings in which they operate than the effect of the incentive structures embedded in the different proprietary forms. We also observe a decline in technical efficiency, probably due to policies aimed at reducing hospitalization rates. Copyright © 2006 John Wiley & Sons, Ltd.