In this article, legal consequences of the new German genetic engineering act are analyzed. In addition environmental economic analysis is presented of those parts of the act that introduce new litigation regulation to farmers. The different kinds of external costs arising from genetic engineering of plants and their allocation to different actors are considered. The paper focuses on the costs resulting from the postulated coexistence of conventional/organic farms and users of biotechnology. Excessive liability of farmers can be avoided, if the producers of genetically modified seeds accept any litigation claims against farmers. Furthermore, negotiations between neighbouring farms can be an option to keep the costs of damage prevention at reasonable levels.