The Centres of Excellence (COE) initiative began in 2010 as a new methodology for providing technical assistance to countries outside the European Union (EU) in chemical, biological, radiological and nuclear (CBRN) risk mitigation. The initiative was designed as a ‘bottom-up’ methodology that combines a (trans-) regional networking approach with national needs assessments and action plans developed by the partner countries, and a project delivery system to transfer EU expertise in a tailored manner to partner countries. Eight Regional Secretariats were established and partner countries were encouraged to (a) form National CBRN Teams to develop an all-hazards, all-government approach; and (b) identify and articulate their specific needs and priorities with regard to CBRN risk mitigation. This system has matured since 2010 and several evaluations have confirmed its potential as an effective capacity-building platform that builds on ownership, partnership and coordination with other donors.