The main objective of the paper is to analyze the impact of 2004?2006 Cohesion Policy on the development of Zielona Gora (a city in western Poland). It concentrates on three key aspects of the development: competitiveness and attractiveness; social and territorial cohesion; and the diffusion of developmental processes. In our research, we have used a variety of methods and sources of information. Our main conclusion is that the Cohesion Policy of that period contributed more to the improvement of the quality of life in Zielona Gora and its surroundings than to its medium- or long-term development.