This interview-based study of three design-oriented KIBS firms proposes a Ushaped project-stage model of co-production intensity in firms offering knowledge-intensive business services (KIBS) requiring a high level of creativity. During the central stage of project execution the creative KIBS firms typically know what needs to be accomplished but do not know what specific path should be pursued to accomplish the task. An intense phase of idea generation and narrowing down of possibilities generally follows the signing of the contract. Interviewees at design-oriented KIBS firms seldom mentioned the client as playing a significant role during the creative phase of the project. The study suggests that, under certain circumstances, both KIBS providers and clients might desire to regulate the level of co-production, and that at certain project stages a reduced level might actually improve the quality of the final output. Other contingencies are also developed