Cluster-based economic development has become an increasingly popular topic for researchers and economic development professionals. Clusters are networks of enterprises and diverse establishments which are close-by in a certain geographical market and connected through relationships of dependence allocating a belonging category of goods and/or services. A growing interest in clusters as an instrument for economic success and growth can be noticed. Especially the new development of cluster-based endeavours i.e. cluster initiatives (CIs) have received much regard. The cluster researcher Christian H. M. Ketels considers as one important point for the success of CIs their involvement into a broader strategy, isolated cluster initiatives have less impact, both overall and on the cluster they are focused on. According to this view, communication and co-operation relationships between different CIs closely located in one region could be really important. In addition, it is also interesting how such different CIs are structured and operate. Therefore, the following two main questions are now interesting to analyze: • What are the differences and similarities between closely located CIs in regard to organization, initiation, participants, financing, limitation, visions, goals, measures, challenges, success factors, problems, achievements, self-satisfaction and self-identification? • To what extent do closely located CIs know of each other, do they co-operate, communicate and collaborate, do they have thematic overlaps and do they exploit advantages, which result from their closely location? These questions cannot be answered in general for all existing CIs. Because of that, the metropolitan region Frankfurt / Rhine-Main is chosen to answer and illustrate the questions for a specific area. This region is chosen because it is one of the economically strongest metropolitan areas in Europe with a lot of closely located CIs, especially in the ICT-industry, and is therefore interesting.