On 7 July 2009, the European Court of Justice (ECJ) issued its very first ruling on the REACH Regulation. To date, the REACH Regulation does not yet apply to polymers. Article 6.3 of the REACH Regulation, however, provides that any manufacturer or importer of a polymer must register with the European Chemicals Agency the monomer substances which compose a polymer and that have not already been registered. The ECJ, gathered in Grand Chamber, ruled that Article 6.3 of this Regulation must be interpreted as applying only to reacted monomers, which are integrated into polymers. The ECJ also stated that this Article conforms to EU Law and notably to the general principles of proportionality and of equal treatment. In line with the previous case law on oral tobacco and the gas allowance trading scheme and contrary to the Advocate General's line of reasoning, the Court refrained from examining whether the legislation was proportionate under a mere scientific ground. The Court rather relied upon arguments based on temporary exceptions to justify the registration of reacted monomers instead of polymers. This ruling confirms the increasing cautious approach the ECJ takes when it is asked to examine the validity of the European Union legislation.