The goal of a health care system is to maximize population health and reduce health inequality. Encountered by rapidly rising medical costs, policy makers have raised concerns over possible overinvestment in health care and have increasingly made the regular evaluation of health care systems central to their work. This study examines the performance of world health care systems by recognizing the multiple-output nature of health production and the existence of cross-country heterogeneity. A pure measure of the technical efficiency that is free from the influence of cross country heterogeneity is estimated. The empirical results show that the effect of the adjustment for heterogeneity significantly alters the efficiency ranks of worldwide health care systems.