This publication presents the data and findings of the risk assessment on N-phenyl-N-[1-(2-phenylethyl)piperidin-4-yl]cyclopropanecarboxamide (cyclopropylfentanyl), carried out by the extended Scientific Committee of the EMCDDA on 21 March 2018. On the basis of the Risk Assessment Report — and on the initiative of the European Commission — on 27 September 2018, the Council decided that cyclopropylfentanyl should be subject to control measures across the Member States.