Key Enabling Technologies - Industrial Biotechnology, Nanotechnology, Micro and Nano-Electronics, Photonics, Advanced Materials, Advanced Manufacturing Technologies - have been put high on the European policy agenda since the late 2000s. They are seen as highly relevant preconditions/inputs to secure the competitiveness in many sectors and areas as they are known to be key enablers for subsequent technological developments in other fields. This policy brief intends to shed a light on the diffusion of Key Enabling Technologies as such as well as in different areas of application. We compare trends of the EU-27 countries with relevant international competitor/partner countries, based on patent applications - from the PATSTAT database - and trademark filings from the ISI-Trademark Data Collection (ISI-TM), which offers a unique data source for the analysis of the diffusion of technologies.