These are the proceedings of the Fifth International Workshop on Cooperative Information Agents, held in Modena, Italy, September 6-8, 2001. Information agent technology has become one of the major key technologies for the Internet and the World Wide Web. It mainly emerged as a response to the challenges of cyberspace from both the technological and human user perspective. Development of information agents requires expertise from different research disciplines such as Artificial Intelligence (AI), advanced databases and knowledge base systems, distributed information systems, information retrieval, and Human Computer Interaction (HCI). The fifth international workshop on Cooperative Information Agents (CIA) continued the tradition by capturing the intrinsic interdisciplinary nature of the above research area by calling for contributions from different research communities, and by promoting open and informative discussions on all related topics. In keeping with tradition, the workshop featured a sequence of regular and invited talks of excellence given by leading experts in the field. This year the topics of the talks are mainly on the challenges of information agents in the upcoming age of ubiquitous and pervasive computing. These challenges are in particular due to the necessity of an efficient utilization, evolution, and trust management of information agents for user-oriented information search, pro- sion, and visualization in networked computing environments with small, mobile, and embedded devices. A different issue concerns the potential of agent-based support of massive distributed data warehousing worldwide.