There is broad consensus that tackling the increasing global environmental problems needs the support of technological innovations. In consequence, environmental technologies are regarded as being one of the fastest growing markets on global scale. Since there is a wide range of technologies that can contribute to progress in this field, there is a strong need for prospective research agendas which are setting priorities in a transparent way. Against this background, the project "Roadmap Environmental Technologies 2020", funded by the German Ministry of Education and Research, aims at supporting the process of identifying strategic policy options for promoting developments and commercial applications in the field of environmental technologies. This has been done in relation to seven environmental fields of action: Climate protection, air pollution control, water management, soil protection, increase of resource productivity, waste management and preservation of nature and biodiversity. As a key-element of the project promising future technological developments are investigated with the help of an extensive survey and with the help of several topic-specific workshops. This is the final report of the project. It includes a documentation of the survey and the workshops. At the end of the report, most important results of the projects are summarised in so-called "priority fields" that offer promising approaches for future research strategies.