The CIPM MRA (Mutual recognition of national measurement standards and of calibration and measurement certificates issued by national metrology institutes) was drawn up by the Comité International des Poids et Mesures (CIPM) and implemented in 1999. It has been signed by most of the National Metrology Institutes throughout the world, and through its web support, the KCDB (BIPM key comparison database), provides formal evidence of the technical equivalence of national measurement standards at the highest level, and of international recognition of the services provided by National Metrology Institutes. The value of the arrangement and the benefits it offers to other sectors, including accreditation, legislation and industry, are now widely acknowledged in the world of metrology.