The construction industry has a long tradition of collaborative working between the members of a construction project team. At the design stage, this has traditionally been based on physical meetings between representatives of the principal design disciplines. To aid these meetings, the information and communications technologies that are currently available have been utilised. These have yielded some success but are hampered by the problems posed by the use of heterogeneous software tools and the lack of effective collaboration tools that are necessary to collapse the time and distance constraints, within which increasingly global design teams work. In particular, there are very few tools available to support distributed asynchronous collaboration. Distributed artificial intelligence, which is commonly implemented in the form of intelligent agents, offers considerable potential for the development of such tools. This paper examines some of the issues associated with the use of distributed artificial intelligence systems within the construction industry. It describes the potential for the use of agent technology in collaborative design and then goes on to present the key features of an agent-based system for the collaborative design of portal frame structures. An example is presented to demonstrate the working and benefits of the prototype system, which makes a significant contribution by allowing for peer to peer negotiation between the design agents.