A table-top exercise on ‘Monitoring a large-scale cross-border contamination in the aftermath of a nuclear accident’ was organized within the FP7-project PREPARE with the focus on the long-term emergency monitoring including transboundary and transnational aspects. From the detailed and content-rich answers from all participants of the table-top exercise, it can be concluded that competent persons with a lot of practical experience in the field were present to play the exercise. Answers were very useful because they were based on the experience from the real situation (e.g. Fukushima accident). It seems that the sampling procedures and measurement strategies are well defined. It was found out that all available communication channels can be established among the crisis centre, teams on the field and other institutions and/or teams involved (e.g. fire brigades, police, army fixed laboratories). From the answers, it comes out that some activities in the emergency are not completely harmonized transnationally, especially dispersion modelling, exchange of data, etc. The majority of the teams claimed that RODOS platform can be applied as the primary tool, but also other dispersion models, in-country developed, would be used in the nuclear emergency. From the answers, it stems out that numbering of specialized teams on the ground and the measurement capacities either in mobile laboratories or fixed laboratories should be concerned in small countries with nuclear installations, and even more pronounced in countries without Nuclear Power Plants (NPPs) on their territories.