This paper examines the effect of customer involvement and knowledge integration onthe innovation performance of the firm in the different phases of the innovationprocess. Based on a survey study of 173 Swedish manufacturing firms across differentindustries, we find empirical support for the importance of customer involvement andknowledge integration for innovation performance in general, and particularly ofcustomer involvement in all phases of the innovation process. Knowledge integrationseems to be particularly important during the development and test phases.