Co-production is very common phenomenon in our everyday lives. We are inclined to assist in the production of services that are delivered to us. The work of Elinor Ostrom shows that it is reasonable to consider co-production as an important element in the production of public services. This paper aims to show what co-production is, the kind of implications co-production has for the performance of public administration, and how co-production can influence the political system as a whole. Co-production, on the one hand, could lead to minor changes in the way the welfare state functions; and, on the other hand, co-production could serve as the basis for a new, complex, polycentric political system.