This paper explores the role of knowledge flows and TFP growth by using direct survey data on knowledge flows linked to firm-level TFP growth data. Our knowledge flow data correspond to the kind of information flows often argued, especially by policy-makers, as important, such as within the firm, or from suppliers, purchasers, universities and competitors. We examine three questions (a) What is the source of knowledge flows? (b) To what extent do such flows contribute to productivity growth? (c) Do such flows constitute a spillover flow of free knowledge? Our evidence show that the main sources of knowledge are competitors; suppliers; plants that belong to the same group and universities. We conclude that the main "free" information flow spillover is from competitors and that multi-national presence may be a proximate source of this spillover.