Under the influence of WTO law, a private infrastructure for the implementation of international standards has emerged. The paper identifies its development out of independent conformity assessment bodies, called certifiers. The basis for the conduct of certification are International Standardization Organization (ISO) standards. The EU has intervened in different ways to integrate these global implementation structures into EU law. The paper discusses many examples from the fields of general product, as well as organic production certification, and emission reduction certification. It moreover develops a typology of the ways of interaction between global, EU and domestic law in the field of certification. The ultimate goal of the employment of the private infrastructure by the EU is the implementation of global–ISO, IFOAM, etc..–standards and international law into domestic law. This raises important issues of the legitimacy of private implementation in EU law.