– Represents the interests of the legal metrology community within international organizations and forums concerned with metrology, standardization, testing, certification and accreditation
– Promotes and facilitates the exchange of knowledge and competencies within the legal metrology community worldwide
– Cooperates with other metrology bodies to raise awareness of the contribution that a sound legal metrology infrastructure can make to a modern economy

The OIML issues several categories of publications:

– International Recommendations, which are intended as model regulations for a number of categories of measuring instruments, and which OIML Member States are morally obliged to implement as far as possible
– International Documents, which are informative and are intended for guidance purposes
– Other publications such as Vocabularies, Guides, Basic Publications and Expert Reports

In addition, the OIML has developed the OIML Certification System (OIML-CS) which is a system for issuing, registering and using OIML Certificates and their associated OIML type evaluation reports for types of measuring instruments (including families of measuring instruments, modules, or families of modules), based on the requirements of OIML Recommendations. In the OIML-CS participants declare that they intend to accept and utilize OIML Certificates and/or OIML type evaluation reports from those participants that are entitled to issue them. The OIML-CS was launched on 1 January 2018, replacing the previous OIML Basic Certificate System and the OIML Mutual Acceptance Arrangement (MAA).

IAF, OIML and ILAC have a tripartite memorandum of understanding.