In this paper we contribute to the longstanding discussion on the role of knowledge to economic growth in a spatial context. We observe that in adopting the European policy strategy towards a competitive knowledge economy, The Netherlands is – as most European countries - mainly oriented towards industrial, technological factors. The policy focus is on R&D specialized regions in their spatial economic strategies. We place the knowledge economy in a broader perspective. Based on the knowledge economy literature, we value complementary indicators: the successful introduction of new products and services to the market (‘innovation’) and indicators of skills of employees (‘knowledge workers’). Using econometric analysis, we relate the three factors ‘R&D’, ‘innovation’ and ‘knowledge workers’ to regional economic growth. We conclude that the factors ‘innovation’ and ‘knowledge workers’ are more profoundly related to urban employment and productivity growth than the R&D-factor. Preferably, urban research and policymakers should therefore take all three knowledge factors into account when determining economic potentials of cities.