COOP 2010 is the 9th edition of the International Conference on Designing Cooperative Systems, being the second European conference in the field of Computer Supported Cooperative Work after ECSCW. The conference brings together researchers who contribute to the analysis and design of cooperative systems and their integration in organizational community, public and other settings, and their implications for policy and decision making. Cooperative systems design requires a deep understanding of collective activities, involving both artifacts and social practices. Contributions are solicited from a wide range of domains contributing to the fields of cooperative systems design and evaluation: CSCW, HCI, Information Systems, Knowledge Engineering, Multi-agents, organizational and management sciences, sociology, psychology, anthropology, ergonomics, linguistics.