In most European countries cost sharing has been introduced in order to reduce the demand for care. Different forms of cost sharing are available, but because of historically grown system characteristics and prevailing values countries differ in the application of specific forms. This review focuses on eighteen European countries, and on the combinations of health system characteristics and present forms of cost sharing. We found that some combinations are more present: different payment systems for primary care physicians go together with different forms of cost sharing, different services have different forms of cost sharing. In countries with a GP as gatekeeper no charges are in use for the GP. No distinct relationship could be found between the financing system (tax-based or insurance-based) and the form of cost sharing or the exclusion of vulnerable populations. It is concluded that there are two ways of filtering 'unnecessary' demand. One is by introducing cost sharing for directly accessible services such as GPs. The second way is by having GPs act as gatekeepers to more specialized, and more costly care.