In the course of the latest economical developments, such as increasing mobility of services and goods, the strategy of building businesses networks gain in importance. The ability to build co-operations, participating in networks becomes more and more to one of the core competences of a business. Networks offer chances, but also create new challenges and uncertainness. Practical examples reveal that co-operating and networking is not an easy task. Against this background the paper in hand enters into the question, which instruments can support the development of business networks, whether networks can boost regional development and why the EU supports regional economic development. After an introduction into the theory about business networks and the EU regional policy the hypothesis is formulated, that "functioning business networks are not a product of chance. The application of appropriate instruments enhances the installation of networks and is of essential importance for the long- term existence of networks". This hypothesis is illustrated through several practical examples.