- Kala Naft Tehran Co.
- East Azerbaijan Province Gas Co.
- West Azerbaijan Province Gas Co.
- Isfahan Province Gas Co.
- Tehran Province Gas Co.
- Zanjan Province Gas Co.
- Sistan and Baluchestan Province Gas Co.
- Fars Province Gas Co.
- Ghazvin Province Gas Co.
- Kurdistan Province Gas Co.
- Kerman Province Gas Co.
- Kermanshah Province Gas Co.
- Gilan Province Gas Co.
- Iranian Oil Pipline & Telecommunications Co.
- Oil Design and Construction Co.
- Natural Gas Storage Co.
- Iran Power Development Co.