The most important natural resources of Iraq are:

• Petroleum (Oil): Iraq has one of the largest oil reserves in the world, with proven reserves around 145 billion barrels. Oil dominates the economy, accounting for over 90% of government revenue and being a major export commodity.

• Natural Gas: Iraq has significant natural gas reserves, about 3.7 trillion cubic meters proven, with much potential untapped. Natural gas is often found alongside oil and is increasingly important for domestic energy and export.

• Phosphates: Iraq holds large phosphate deposits used primarily for fertilizer production. These mineral resources contribute to industrial use and agriculture.

• Sulfur: Iraq possesses one of the world's largest sulfur reserves, mined mainly for industrial and chemical applications.

• Agricultural Land & Water: Fertile land mainly in the Tigris-Euphrates basin supports crops like wheat, barley, rice, dates, and fruits. Water resources from the Tigris and Euphrates Rivers are critical but face challenges such as drought and upstream damming.

Additionally, Iraq has mineral resources such as copper, iron ore, zinc, lead, limestone, gypsum, and rare earth elements, which are largely untapped but hold industrial potential.

In summary, Iraq's key natural resources are its vast oil and natural gas reserves, significant phosphate and sulfur deposits, fertile agricultural land supported by important water resources, and a variety of other minerals with industrial uses.