İzmit Refinery began production in 1961 with capacity to process 1 million tons/year crude oil. As a result of significant capacity increases and the conversion unit investments over the years, the Refinery's design capacity was registered at 11.3 million tons/year.

Producing to Euro V standards, İzmit Refinery located in a consumption center, accounting for 33% of Turkey's consuption of petroleum products.

With the aim of meeting Turkey's growing requirement for petroleum product, İzmir Refinery was brought intro operation in 1972. The refinery, which stardet production with an annual crude oil processing capacity of  3 million tons is now registered as having an annual refining capacity of 11.9 million tons following significant capacity increases and unit modernizations carried out over the years.

Established in 1986 to meet the petroleum demands of the Ankara, Central Anatolia, Eastern Mediterranean and Eastern Black Sea regions, the Kırıkkale Refinery has become a facility with mid level complexity by Mediterranean standards with the addition of hydrocracker, isomerization, diesel desulphurization and CCR reformer units.

Commissioned in 1955 with a crude oil processing capacity of 330 thousand tons, the Batman Refinery was the first refinery to be founded in Turkey. Following an initiative to overcome production bottlenecks in 1960 and the commissioning of a new crude oil processing unit in 1972, Batman Refinery’s crude oil processing capacity reached 1.4 million tons/year.