This publication presents the data and findings of the risk assessment on methyl 1-(2-phenylethyl)-4-[phenyl(propanoyl)amino]piperidine-4-carboxylate (carfentanil), carried out by the extended Scientific Committee of the EMCDDA on 7-8 November 2017. In March 2018, at its 61st regular session, the Commission on Narcotic Drugs (CND) decided to place carfentanil in Schedule I and Schedule IV of the Single Convention on Narcotic Drugs of 1961 based on a recommendation by the World Health Organization. This recommendation was substantially supported by European data provided by the EMCDDA.