The EC Regulation on Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) came into force on 1 June 2007, marking the end of three years of intense negotiations between the Council and the European Parliament. One of the most hotly debated topics was the registration of substances, where the original Commission proposal sparked an extensive debate about the volume-based structure proposed. Risk-based prioritization was a concept proposed by both industry and academia to replace this, but due to its own fundamental lack of workability, its inclusion was rejected. However, a lightening of the low tonnage levels was agreed, along with the practical implementation of the ‘one substance, one registration’ principle. Overall, it can be seen that despite the many changes proposed, analyzed, discussed and accepted during the three years of intense negotiations, the basic architecture that the Commission proposed remains and registration will provide an enforceable framework for companies and will ensure a level playing field for chemicals across Europe.