This communication describes the European Registry of Materials and the corresponding ERM as a persistent, unique identifier for nanomaterials and how various nanosafety projects have begun to use it. The identifier fills a need by allowing the projects to apply the FAIR principles to research output while it is being generated. The assignment of ERM identifiers already when selecting nanomaterials to test within a project facilitates the consistent identification of materials by multiple partners within the same project. Tools like eNanoMapper Template Wizard and an integrated ERM lookup on data entry alleviate the problem that ERMs are not easy to remember. It is important to note that how the ERM identifier is used is left to the user currently, and the use cases show examples of how the identifier is adopted. The full value will become clear when many more research outputs are publicly shared, as it will allow us to connect results accurately. The active uptake of the identifier in multiple data reuse case studies, and the intention of projects like NanoInformaTIX and HARMLESS to start using them, bodes well for the future of this persistent nanomaterial identifier.