The IERS was established in 1987 by the International Astronomical Union (IAU) and the International Union of Geodesy and Geophysics as the International Earth Rotation Service; and began operation on 1 January 1988. In 2003, it was renamed to International Earth Rotation and Reference Systems Service.

The primary objectives of the IERS are to serve the astronomical, geodetic and geophysical communities by providing the following:

• The International Celestial Reference System (ICRS) and its realization, the International Celestial Reference Frame (ICRF).
• The International Terrestrial Reference System (ITRS) and its realization, the International Terrestrial Reference Frame (ITRF).
• Earth Orientation Parameters (EOPs) required to study variations in Earth’s orientation and to transform between the ICRF and the ITRF.
• Geophysical data to interpret time and space variations in the ICRF, ITRF, or EOPs, and to model such variations.
• Standards, constants, and models (i.e., conventions) encouraging international consistency.