National Iranian Oil Refining & Distribution Company (NIORDC) was established on the basis of the principle of separating the up-stream (exploration and production of crude oil and gas) from the down-stream (refining, crude and products transporting, export, import and distribution of petroleum products) activities in March of 1991 . Later that year, NIORDC officially began its activity as one of the four major subsidiaries of the Ministry of Petroleum. NIORDC fulfils its mission through three operating subsidiaries and nine oil refining companies.

 NIORDC offers its services using 20,000 experienced employees. In view of the increasing demand for petroleum products, NIORDC has embarked upon expanding, upgrading and optimizing its existing refineries, as well as building new grass-root refineries.

In addition to crude oil refining, NIORDC's activities are also focused on engineering, construction, distribution and transportation of oil products which are embodied into its three major subsidiaries: