This paper presents a Spreadsheet Application For Evaluation of BIOdiversity (BIO-SAFE) on the basis of political and legal criteria derived from national and international policy plans, laws, treaties and directives. The BIO-SAFE is developed as a management tool to optimise mutual attuning of nature conservation policies and other interests in spatial planning. Fields of application of BIO-SAFE comprise designs and evaluations of physical planning projects, environmental impact assessments and comparative landscape-ecological studies. Taxonomic groups involved in BIO-SAFE are higher plants, dragonflies and damselflies, butterflies, fish, amphibians, reptiles, birds and mammals. The development of BIO-SAFE was based on species characteristic of rivers and their floodplains, but the principles of the method can easily be applied to other ecosystems as well. The BIO-SAFE has been applied on behalf of a combined flood risk reduction and ecological rehabilitation plan for the Rijnwaarden floodplains (River Rhine, the Netherlands). Application to flora and fauna data available for this area showed that the BIO-SAFE method enables the user to express politically and legally based biodiversity values in quantitative terms and to compare biodiversity values for various taxonomic groups, landscape-ecological units (e.g. ecotopes) and physical planning scenarios. By linking habitat preferences of the species selected to ecotopes, the method also allows the user to derive relevant information at the ecosystem level. Because of its policy-based character, BIO-SAFE yields complementary information to more established ecological biodiversity indices.