COMET will strengthen the pan-European research initiative on the impact of radiation on man and the environment by facilitating the integration of radioecological research. COMET will build upon the foundations laid by the European Radioecology Alliance (ALLIANCE) and the on-going FP7 STAR Network of Excellence in radioecology. By collaborating with the European platforms on nuclear and radiological emergency response (NERIS) and low dose risk research (MELODI), COMET will significantly aid preparation for the implementation of the Horizon 2020 umbrella structure for Radiation Protection.In close association with STAR and the ALLIANCE, COMET will take forward the development of a Strategic Research Agenda as the basis for developing innovative mechanisms for joint programming and implementation (JPI) of radioecological research. To facilitate and foster future integration under a common federating structure, research activities developed within COMET will be targeted at radioecological research needs that will help achieve priorities of the NERIS and MELODI platforms. These research activities will be initiated in collaboration with researchers from countries where major nuclear accidents have occurred. Flexible funds, unallocated to specific tasks at project initiation, have been included within the COMET budget to facilitate RTD activities identified through the JPI mechanisms developed that are of joint interest to the ALLIANCE, NERIS and MELODI. It will also strengthen the bridge with the non-radiation community. Furthermore, COMET will develop strong mechanisms for knowledge exchange, dissemination and training to enhance and maintain European capacity, competence and skills in radioecology.The COMET consortium has 13 partners, expanding from the organisations within the FP7 STAR project. In particular, COMET partners from countries which have experienced major nuclear accidents (i.e. Ukraine and Japan) and/or who hold Observatory sites.