Political and academic debate about cost-sharing in health care is becoming very popular because of the massive health care expenditure growth. In this paper, we aim to validate the use of cost-sharing in health care by assessing the effects that different policies of cost-sharing have produced around the world. We review, then, several empirical papers dealing with cost-sharing effects with respect to three main issues: moral hazard-contrast, redistributive effects and health care cost-containment. The findings of empirical literature indicate that the use of cost-sharing in health care gives rise to the classical political economy trade-off between equity and efficiency. However, while distributive effects are demonstrated, gains in terms of efficiency and cost containment are not clearly verified by empirical literature; thus, cost sharing policies seem to be desirable only when combined with mechanisms that promote access to the most vulnerable categories.