The first International Workshop on Collaborative Peer-to-Peer Information Systems, COPS05 was held in Link?ping University as part of WETICE-2005. It was the first meeting devoted to the study of the emerging field of Cooperative Information Systems and P2P networks or Cooperative P2Pbased Information Systems (COPS). P2P Systems are popular because of the many benefits they offer: adaptation, self-organization, fault tolerance, and massive distribution and replication of large number of resources. The P2P environment is particularly challenging to work in Collaborative Information Systems because of the scale of the network and fault-tolerant nature of peers that characterize most P2P systems today. However, the P2P systems research community has focused on search and security aspects. Collaboration has been mainly viewed as an architectural paradigm instead of as an application framework for P2P systems. There is a need for a next generation tools for the development of applications that must integrate, for example, web servers network and p2p clients. Research communities working in database and distributed systems have included these topics in their agenda. However, a more specialized workshop could be an interesting place to exchange new ideas in the field of COPS.