This is a list of fentanyl analogues (sometimes referred to as Fentalogs), including both compounds developed by pharmaceutical companies for legitimate medical use, and those which have been sold as designer drugs and reported to national drug control agencies such as the DEA, or transnational agencies such as the EMCDDA and UNODC. This is not a comprehensive listing of fentanyl analogues, as more than 1400 compounds from this family have been described in the scientific and patent literature, but it includes many notable compounds that have reached late-stage human clinical trials, or which have been identified as having been sold as designer drugs, as well as representative examples of significant structural variations reported in the scientific and patent literature...