Cluster Organizations, as a means of promoting competition and innovation in industrial clusters, have become increasingly popular over the world. Cluster organizations aim to increase growth and competitiveness of clusters within a region, and have become a central part of economic policy-making across the world. Recently, the concept has been used to a larger extent as a tool for economic development and poverty alleviation. This thesis seeks to examine the cluster organizations that are part of the Sida funded program Innovation Systems and Cluster development in Tanzania (ISCP-Tz), by evaluating performance, goals and development of the program based on cluster facilitators perceptions, and assess linkages and actor collaborations between clustered actors. The data in this thesis is collected through a telephone-administered questionnaire, as well as interviews and visits to cluster sites. The results show a positive impact on cluster firms performance as assessed by cluster facilitators, but show that actor collaborations in many cases are inadequate and need to be improved.