The literature on "Innovation Systems" is divided into several directories. Differences occur through the definition of the system's borders. This paper introduces a methodology how to differentiate between regional and technological effects of cooperative innovation activities and analyzes furthermore how different dimensions of regional knowledge affect the regional effects on cooperative innovation activities. We find evidence that the related variety of knowledge available within a region and its combination with a proxy of the amount of knowledge foster regional effects of cooperative innovation activities. Additionally, we find that the development of German regions fits with the suggestions of the Regional Innovation System (RIS) approach.