In this article the changes that have been implemented in the Dutch social security system are analyzed. The extensive changes are characterized as a form of "managed liberalization." This characterization points to the paradoxical nature of these changes. On the one hand a certain liberalization can be observed (an increase of social insurance and the administration of social security via the market) while on the other hand the control of the system by the state is also increasing. This process of managed liberalization, however, takes place under an umbrella of lasting universal social protection: entitlements are still determined by law and remain collective. In this article the changes in the Dutch social security are described extensively, interpreted theoretically and analyzed in their consequences for the level of social protection. By following the process of institutional change the system of social security has undergone, the authors also try to find out what the causes of the changes are and what determines the direction the process has taken.