National Iranian Oil Engineering and Construction Company is responsible for implementation of all infrastructure projects in the downstream sector of the petroleum industry including refining, storage and distribution of crude oil and petroleum products across the country.

Since the past, the activities of the company have started by designing and constructing oil storage and sale place for the oil and have been continued by construction of the first refinery in Tehran and oil and gas pipeline during 1960’s as the management of specific projects in National Iranian Oil Company continued.

After Islamic Revolution in Iran, major design and implementation related activities, which were done in the past by foreign companies, was undertaken by internal experts. And in line with the general policies of the Islamic Republic of Iran's Ministry of Petroleum, self-sufficiency in all oil activities in Iran, particularly in refinery construction projects and the issue of knowledge transfer to local experts, was considered by many.