This Practice Note explains the trading obligation for derivatives under the Markets in Financial Instruments Regulation (EU) 600/2014 (EU MiFIR) (which, together with the recast Markets in Financial Instruments Directive 2014/65/EU (EU MiFID II), took effect on 3 January 2018) and covers: (1) the regulatory context of the trading obligation, (2) the counterparties to which the trading obligation applies (certain financial counterparties and certain non-financial counterparties), (3) the requirement that a derivative contract which is declared to be subject to the trading obligation must already be subject to the clearing obligation under the European Market Infrastructure Regulation (EU) 648/2012 (EU EMIR), (4) which derivatives are subject to the trading obligation, (5) the treatment of package orders or transactions, (6) the exemption for post-trade risk reduction services, (7) the regulated trading venues on which derivatives must be traded (regulated markets, multi-lateral trading facilities (MTFs), organised trading facilities (OTFs) and equivalent third country trading venues), (8) the reforms to the trading obligation for derivatives made by Regulation (EU) 2024/791 (the MiFIR Review). For general information on