On the 21-25 September 2015 the Mariolopoulos – Kanaginis Foundation for the Environmental Sciences coorganized with the International Atomic Energy Agency, the International Union of Radioecology, the Greek Atomic Energy Commission and the Journal of Environmental Radioactivity Comenius University of Bratislava the “International Conference ENVIRA 2015 on Environmental Radioactivity” under the auspices of the Aristotle University of Thessaloniki. The meeting was attended by more than 250 participants and concentrated on the effects of transport and dispersion of radio accidents in the environment following nuclear accidents.