This paper is an output of a research project supported by INTAS (04-79-6991) which investigates the extent, nature and forms of cross-border cooperation in border regions in Ukraine, Belarus and Moldova with EU new members and upcoming accession states, in order to assess its contribution to entrepreneurship, economic and social transformation. Requirements for successful co-operation, especially the role of trust and learning, will be assessed in relation to other factors influencing the success of these relationships. The paper summarises the results of the literature review undertaken in order to gain a deeper understanding of what constitutes cross-border cooperation and the role trust and learning play herein (chapter 2), the effects of EU enlargement on cross-border co-operation (chapter 3), regional entrepreneur-ship developments in the three countries surveyed after EU enlargement (chapter 4) and policy efforts to support cross-border co-operation (chapter 5).