Convergence in per capita income across countries turns on whether technological knowledge spillover are global or local. This paper estimates the amount of spillover from R&D expenditures in major industrialized countries on a geographic basis. A new data set is used which encompasses most of the world's innovative activity at the industry-level between the years 1970 and 1995. First, I find that technological knowledge is to a substantial degree local, not global, as the benefits from foreign spillover are declining with distance: on average, a 10% higher distance to a major technology-producing country such as the U.S. is associated with a 0.15% lower level of productivity. Second, technological knowledge has become more global over the sample period. As a determinant of productivity, foreign R&D has significantly gained in importance relative to domestic R&D, and the extent to which knowledge spillover decline with distance has fallen by 20%. The finding of a falling but still high degree of localization has important implications for macroeconomics and growth, trade, and regional economics.