Over the last decades, there has been a vast amount of literature on the subject of Research and Development (R&D) expenditure as a main driver of economic growth, both at national and sub-national levels. This being so, the main purpose of this manuscript is to investigate the role played by R&D as a cohesion instrument. To accomplish this aim, the paper assesses the link between patents (as a proxy for R&D) and economic growth across the Spanish provinces (NUTS3) over the period 1995-2010. In other words, we want to evaluate whether provinces with high patent production grow at a higher rate than those with low innovative performance. In addition, we want to test for the presence of spatial spillovers, and to assess if the effect of patents on economic growth depends on the development degree of provinces. The results show, firstly, that patents act as a growth driver. Secondly, that there is no evidence of spatial spillovers. And, thirdly, that the effect of patents on growth seems to be higher for developed than for less developed provinces. In view of these findings, major efforts should be devoted to promote a cohesion policy focused on R&D investment in the less developed territories.