Since the mid-1970s more and more intertidal and subtidal marine areas worldwide have been reserved by law or by other means to protect the environment and/or to boost overexploited fish populations. Today, about 4,600 marine protected areas (MPAs) totalling some 2.2 million km2 or 0.6% of all oceans and sea areas is under protection. Although this can be considered a first important step, it is still far behind the 12% area of protected land and the target of 20-30% of each marine habitat to be protected by 2012. Nonetheless there is hope that more countries will follow the example of Germany and New-Zeeland, who announced recently to be putting one third of their marine environment under protection. Also Belgium seems to be on track by the designation by the Minister for North Sea Affairs of four new marine Natura-2000 areas on top of the existing 'Stroombank-Trapegeer' Special Area of Conservation in 2005. Meanwhile the latest studies demonstrate clearly how powerful MPA's - the small ones, as well as the big ones - can be as a managing tool for healthy, sustainable marine ecosystems in all climate regions of the world. The major challenge for the near future will undoubtedly be to bring together nature conservancy objectives and fisheries management into one integrated sustainable practice for the benefit of the marine environment and those who make their living out of its natural resources. A practice in which MPAs can play a major role.