New tendencies in global economy cause that the level of competitiveness of national enterprises depends on more complex and mutually combined factors, that do not depend on enterprises solely. Small and medium enterprises (SME) operate in more and more difficult conditions all around the world. The competitiveness pressure of the market groves, which is generally generated by mergers and strategic alliances between transnational corporations, both in modern and traditional branches as well. Further, the processes of European integration and market globalization cause that essential for SME survival is the ability to compete, but not traditionally only on regional or even national market, but also on world market. The problems of SME competitiveness, region, interactions between those enterprises, region and national competitiveness meet in the cluster concept. The concept is so important for SME because extreme amount of them operate on the local market, however interoperating within a cluster enables to enter the world market. But the condition for cluster success as a whole and for enterprises performed within the cluster is presence of synergy. The aim of this article is to underline the role of the synergy, that presence is an indispensable factor for competitiveness of the SME operating in a defined cluster. It was necessary to discuss what conditions are favourable in creating synergy, and at the same time how they contribute to build such synergy influences on leveraging the competitiveness of cooperating enterprises. Furthermore, the analysis of subjective chosen clusters has been conducted as an example of laborious process of synergy obtaining. The finding suggests that the evolution of behaviour among enterprises is needed along with the changes in economic policy conducted on national and regional level; however, it must be the policy that takes into account the voice of the regional interest groups. It should be pointed out that enterprises themselves are responsible for taking advantage from the potential in localisation in the cluster. The conviction is that the enterprises influence on the interaction power of the factors located in the region, that affect competitiveness of the company.