In the late 1980s, a new conceptual framework appeared in the science, technology, and innovation studies: the National Innovation System. The framework suggests that the research system's ultimate goal is innovation, and that the system is part of a larger system composed of sectors such as government, university, and industry and their environment. The framework also emphasized the relationships between the components or sectors, as the ``cause'' that explains the performance of innovation systems. Most authors agree that the framework came (...) from researchers like Freeman, Nelson, and Lundvall. In this article, the author want to go further back in time and show what the ``system approach'' owes to the Organisation for Economic Co-operation and Development and its very early works from the 1960s. This article develops the idea that the system approach was fundamental to OECD work, and that, although not using the term National Innovation System as such, the organization considerably influenced the above-mentioned authors. (shrink)