This contribution analyses the comprehensive chemicals legislation proposed by the EU Commission, "REACH", from the perspective of WTO law. First, it inquires whether the treatment of foreign substances and foreign articles in REACH can be reconciled with one of WTO's key requirements, i.e., non-discrimination. Second, it tests specific aspects of the registration obligation established by REACH (i.e., the "volumes-driven" approach, the follow-up to the registration process, the underlying foundations of REACH's cost-benefit analysis) against the proportionality rule embodied in the WTO's Agreement on Technical Barriers to Trade. Third, it asks whether the protection of confidential business information in REACH is compatible with the WTO rules on intellectual property protection (notably, the TRIPS Agreement). It results from the present analysis that REACH poses considerable challenges not only under EU law, but also under WTO law.