Abstract The present paper provides new estimates of the impact of investment in R&D on long-term economic growth. In particular, we estimate a dynamic empirical growth model using panel data for OECD countries from 1970 to 2004. This study is the first to investigate whether the specialization of R&D activities (i.e. share of R&D investment in the high-tech sector) has an additional effect on GDP per working age population. Using a system GMM estimator in order to control for endogeneity, we find that both the ratio of business enterprises’ R&D expenditures to GDP and the share of R&D investment in the high-tech sector have strong positive effects on GDP per capita and GDP per hour worked in the long term.