In the introductory section, the Authors discuss major determinants affecting the operation of enterprises in the contemporary economy, including information, time, globalisation and - above all - organisational integration and network formation tendency. The discussion is complemented by a presentation of concepts which are dealt with in the subsequent sections. In the following part, relations that can occur within the supply chain are described. Based on available literature, an in-depth account of the concept and importance of bargaining power is presented, focused on its impact on the development of supply chain relations and the resulting potential role of supply chain links, the leader role in particular. Finally, results of literature reports and own empirical studies are used to describe possible strategies used in the supply chain.