This Practice Note outlines the requirements under Assimilated Regulation (EC) 1907/2006 of the European Parliament and of the Council concerning the registration, evaluation, authorisation and restriction of chemicals (UK REACH) for manufacturers and importers of chemicals to register substances with the Health and Safety Executive (HSE). It is part of a series of notes on REACH. It covers exemptions from registration, transitional arrangements, submitting the registration dossier, as well as the duty of the Secretary of State to carry out reviews of specific aspects of UK REACH and publish a general report on its operation.