These are the proceedings of the 12th international workshop on cooperative informationagents(CIA2008), heldattheCzechTechnicalUniversityinPrague, Czech Republic, on September 10-12, 2008. In today's world of ubiquitously connected heterogeneous information s- tems, business services and computing devices, the intelligent coordination and provisionofrelevantadded-value informationor servicesto the user atany time, anywhere is of key importance to a variety of applications. This challenge is - visioned to be coped with by means of appropriate intelligent and cooperative information agents. An intelligent information agent is a computational software entity that is capable of accessing one or multiple, potentially heterogeneous and distributed information sources, proactively acquiring, mediating, and maintaining relevant information or services on behalf of its human users, or other agents, preferably just in time and anywhere. One key challenge of developing intelligent and - operative information systems is to balance the autonomy of networked data, information, and knowledge sourceswith the potential payo?of leveragingthem by the appropriate use of such agents. Researchonintelligentinformationagentsandsystemsisinherentlycrossd- ciplinary covering themes from domains such as AI, Multiagent Systems, HCI, SemanticWebTechnologies, WebServices, InformationSystems, KnowledgeD- covery, Information Retrieval, and P2P Computing.