This Best Practice document for the European Code of Conduct for Energy Efficiency in Data Centres is a reference document to assist data centre operators in identifying and implementing measures to improve the energy efficiency of their data centres. This Best Practice document contains a full list of the identified and recognised data centre energy efficiency best practices within the Code of Conduct. The best practice list provides a common terminology and frame of reference for describing an energy efficiency practice, to assist Participants and Endorsers in avoiding doubt or confusion over terminology. Customers or suppliers of IT services may also find it useful to request or provide a list of Code of Conduct Practices implemented in a data centre to assist in procurement of services that meet their environmental or sustainability standards. The Best Practice document is also a reference for the Taxonomy Delegated Act for climate mitigation in data centres and it is mentioned in the 2023 Energy Efficiency Directive in its Article 12.