The integrated and comprehensive real-time on-line decision support system, RODOS, for off-site emergency management of nuclear accidents is being developed with support from, inter alia, the European Commission and the German Ministry of Environment. Designed as a generic software tool, the RODOS system will be applicable from the very early stages of an accident up to many years later and from the vicinity of a release to far distant areas. Decision support will be provided at various levels, ranging from the largely descriptive, with information on the present and future radiological situation, to an evaluation and ranking of the benefits and disadvantages of different countermeasures' options. This paper provides an overview of the RODOS system, a description of its most important software components, the status of its development and its potential role for improving emergency response in Europe.