The present is a “product” of the International Congress entitled: “MANAGEMENT PLANT AND BOARDS OF NATURA 2000 SITES” organized on Mars 19-20, 2004, in Volos and Tsangarada ( Mount Pelion) by the University of Thessaly (Department of Planning and Regional Development) and the “Legal Observatory Natura 2000”. The “Legal Observatory Natura 2000” is a Network of legal experts from different Member States of the EU (gathered at the International Centre of Comparative Environmental Law-C.I.D.C.E.), whose mission consists in the evaluation and the followup, in European and Comparative Law of the establishment of the Natura 2000 Network, as provided by the Council Directive 79/409/EEC on the conservation of wild birds (Birds Directive) and of the Council Directive 92/43/EEC on the conservation of natural habitats and of wild fauna and flora (Habitats Directive).