The sale of oil and gas is one of the most important components of the Syrian economy. Unfortunately, since the discovery of these resources, the Syrian people have not benefited from the revenues earned. This study deals with the development of oil and gas production and the geographical distribution of fields, as well as production control, deterioration of production, refining and selling mechanisms, and the resulting health and environmental impacts following Islamic State’s (IS) control of the majority of oilfields in Syria. Since summer 2015, IS controls 80% of the fields with a production of 65,000 barrels per day (b/d); the Assad regime controls 8% of fields with 10,000 b/d; and Kurdish forces dominate the remaining 12% with 25,000 b/d. IS depends on oil as a major source of financing for its military and civilian activities, and has also managed to set up an extensive network of middlemen in neighbouring territories and countries, with the aim of trading crude oil for cash and other resources. IS produces and exports within its areas of control and sells part of the oil to the Assad regime, and another portion to the liberated areas, as well as to Iraq and Turkey.