Technology spillovers are an important source of economic growth. This article presents a new method to measure technology spillovers at the macroeconomic or sectoral level by means of a so-called technology flow matrix. The main novelty relative to existing technology flow matrices is that the matrix in this article provides insight into the time dimension of the spillover process. The matrix is used to assess whether or not R&D spillovers lead to a more equal distribution of technology investment over sectors.