This Practice Note looks at the health and safety file (which can be physical or electronic) which the Construction (Design and Management) Regulations 2015, SI 2015/51, (CDM Regs) require to be prepared in relation to construction projects involving more than one contractor. It considers who is responsible for the preparation and maintenance of the health and safety file, when they must compile it, the information that the file must contain, and also sets out some practical considerations.