According to Article 31 (3b) of Directive 2001/18/EC, Member States shall establish public registers for recording the cultivation of GM plants grown under part C.  The primary purpose is the monitoring of potential adverse environmental effects of such GMOs.  The German GMO location register was established in February 2005 by the Federal Office for Consumer Protection and Food Safety (BVL).  Actual data for the intention of GMO planting as well as the real cultivation area per year and postal code area are publicly available via internet.  The German Gene Technology Act has the aim to broaden the location register towards an instrument of coexistence and transparency.  After three years of experience we report on notification statistics, public interest, encountered difficulties and future plans of development.  In addition we describe the situation in other EU Member States regarding the introduction and the access to public location registers.  Requirements on the data base and data harmonization are discussed in the light of using location registers as a monitoring instrument throughout Europe.