Regional disparities and spatial clustering are ubiquitous in today s world. This study contributes with empirical findings on the distribution of European research and patenting activity since the 1980s at the regional level. Besides a general theoretical part, it offers a quantitative clustering analysis, which makes use of EPO patent applications and a harmonized regional and technological classification. Moreover, the pan-European study incorporates a structural analysis of inter-regional co-patenting networks at the regional and technological level that covers the 1990s and 2000s....