Industrial and Corporate Change Advance Access published February 3, 2006

Co-design by a firm and its suppliers has become a widely accepted means of developing new products, especially technologically-complex products. Much existing research emphasizes stable and trusting relationships as a "one-best way" for governing these co-design relations. This article questions this view. The article argues that co-design relations are likely to be diverse, unstable, and conflictual due to the inherent nature of the co-design activity. The inherent diversity of co-design relations is explained by the need to organize for distinct coordination needs. Three coordination processes, each directed toward a different coordination need, are derived from the study of a single aerospace co-design project. Interactions between these processes are shown to systematically produce conflict and instability in co-design relations. The main implication of the study is that co-design performance depends on a firm and its suppliers dealing explicitly with these interactions but that there is no "one-best way" of doing so. Copyright 2006, Oxford University Press.