This paper investigates how the strength and intrinsic characteristics of firms� knowledge bases and processing routines have evolved with the past inflow of employees. The empirical analysis is based on linked public register and innovation survey data for Norway. It finds that recruitment from universities, research institutes and higher education institutions has increased the capacity of firms to generate technical inventions. Yet, the organizational knowledge bases and processing routines on which commercial innovation output depends have been strengthened only by the recruitment that has occurred from related industries. Implications for research, management and policy are drawn.