Will genetic engineering be the best hope for a 'sustainable agriculture using less herbicides, pesticides and fertilizers? Some already answer positively. With the development of genetic engineering, the use of transgenic microorganisms, plants and animals equipped with a variety of desirable properties would allow agriculture to be guided towards smoother farming methods (integrated production) resulting in quality improvements and productivity gains. But those new technologies are not yet ready. Though the introduction of transgenic plants cannot be compared with the introduction of new species, adventitious or exotic plants, the main question remains of impact and risk measurement for environment. Research groups are working on the evaluation of those genetic pollution risks as on the controlling means of a voluntarian vertical or horizontal spreading of transgenic organisms. Because such an evaluation can be reliable only if it matches reality as close as possible, tests in pilot fields, in restricted and watched areas are carried out. The biological barrier is secured by a plug zone around the test area. Is this protection enough?In Switzerland, the CSSB (Commission Suisse Interdisciplinaire pour la Securité Biologique dans la Recherche et dans ses Applications Techniques) only gives a recommendation without any legal strength to the spreading demands since there are no adapted regulations. The federal law on environment protection (LEP) revision for European conformity, should compensate this lack. Actually, the enforcement of European texts (90/220/CEE; 94/151CE) implies preliminary obligatory authorization, presentation of precise informations on receiver and giver organisms, spreading kinds and setting specifications, organism/environment interactions and control measures. The term “organism” is from now on taken in a large meaning, including natural organisms as well as genetically modified organisms, cellular or non-cellular. Will Switzerland seize to coordinate environment protection law with land use law? This one could actually turn out to be a very useful complementary protection tool allowing to lighten the choice for the area where to practice the field tests. Agricuitural or not to be build areas seem to be the most appropriate ones but they need to be reviewed for this purpose. According to article 18 of the land use law, special areas could even be created to take into account protected and living areas, intersecting agroecosystems, water catchments, ... If the adaptation of European texts to the environment protection law offers new prospects in terms of environment protection by the CSSB control, which authority will estimate social value, socio-economic and ethic problems of such projects?