The concept of collaborative design has recently come under renewed attention in the field of computer aided architectural design support. Although collaborative design deals with the same aspects of cooperation by various participants in the design process as previously studiedin, for example, concurrent engineering and multi-disciplinary design, it nevertheless puts a different research emphasis. Collaborative design looks at how the process can be improved in such a way that collaboration –working together in a manner to enhance each participants contribution to the design– emerges from the process. In engineering design practice, thismeans a shift forward in the design process where engineers are asked earlier for their input in the design solution. For CAAD research, the phenomenon of collaborative design poses the question how design tools and environments can be made in such a way that collaboration will occur. In this paper, the aims is to describe the concept of collaborative design in architecture, and to give an outline of the perceived requirements in the organisation of design and Computer Aided Design Support to achieve collaborative design.