This article deals with cross-border cooperation analysed in terms of cooperation that takes place between organisations in particular societal institutions and in a cross-border context. The concept on which this study is based is path dependence understood in terms of its function in explaining the creation of institutions in societal life. The aim of this article was to determine the sustainability of trans-border partnerships initiated within the framework of the PHARE CBC Programme in Poland. Three major rules governing the system of cooperation in border regions in Poland have been identified in the course of this analysis: the dependence of the activities of organisations cooperating in border regions on external financing; a lack of cross-border organisations recognised as border-region hosts whose position would entitle them to make key decisions concerning the whole area under research; and the significance of the border-region and attractive neighbour locational rent for territorial cooperation.