At a meeting held inParison 14 October 1999, the directors of the national metrology laboratories from 38 member states of the BIPM and the representatives of two international organisations signed the mutual recognition arrangement for national measurement standards and measurement and calibration certificates issued by national metrology laboratories (MRA). Representatives from other laboratories have signed the CIPM MRA in the meantime. This mutual recognition arrangement meets the increasing need for an open, transparent and global system capable of providing its users with reliable quantitative information on the equivalences between the national metrology services and of forming a technical basis for broader agreements in the realms of trade, commerce and international regulations. As of today, the arrangement has been signed by representatives of 74 laboratories in 45 member states, 27 associates of the general conference and two international organisations. 123 laboratories designated by the signatories are also party to the arrangement.