The number of personnel in the Iraqi military before the war was uncertain, but it was believed to have been poorly equipped.
The International Institute for Strategic Studies estimated the Iraqi armed forces to number 538,000 (Iraqi Army 375,000, Iraqi Navy 2,000, Iraqi Air Force 20,000 and air defense 17,000), the paramilitary Fedayeen Saddam 44,000, Republican Guard 80,000 and reserves 650,000.

Another estimate numbers the Army and Republican Guard at between 280,000 and 350,000 and 50,000 to 80,000, respectively, and the paramilitary between 20,000 and 40,000.
There were an estimated thirteen infantry divisions, ten mechanized and armored divisions, as well as some special forces units.
The Iraqi Air Force and Navy played a negligible role in the conflict.

During the invasion, foreign volunteers traveled to Iraq from Syria and took part in the fighting, usually commanded by the Fedayeen Saddam.
It is not known for certain how many foreign fighters fought in Iraq in 2003, however, intelligence officers of the U.S. First Marine Division estimated that 50% of all Iraqi combatants in central Iraq were foreigners.

In addition, the Kurdish Islamist militant group Ansar al-Islam controlled a small section of northern Iraq in an area outside of Saddam Hussein's control.
Ansar al-Islam had been fighting against secular Kurdish forces since 2001.
At the time of the invasion they fielded about 600 to 800 fighters.
Ansar al-Islam was led by the Jordanian-born militant Abu Musab al-Zarqawi, who would later become an important leader in the Iraqi insurgency.
Ansar al-Islam was driven out of Iraq in late March by a joint American-Kurdish force during Operation Viking Hammer.
The number of personnel in the Iraqi military before the war was uncertain, but it was believed to have been poorly equipped. The International Institute for Strategic Studies estimated the Iraqi armed forces to number 538,000 (Iraqi Army 375,000, Iraqi Navy 2,000, Iraqi Air Force 20,000 and air defense 17,000), the paramilitary Fedayeen Saddam 44,000, Republican Guard 80,000 and reserves 650,000.
Another estimate numbers the Army and Republican Guard at between 280,000 and 350,000 and 50,000 to 80,000, respectively, and the paramilitary between 20,000 and 40,000. There were an estimated thirteen infantry divisions, ten mechanized and armored divisions, as well as some special forces units. The Iraqi Air Force and Navy played a negligible role in the conflict.
During the invasion, foreign volunteers traveled to Iraq from Syria and took part in the fighting, usually commanded by the Fedayeen Saddam. It is not known for certain how many foreign fighters fought in Iraq in 2003, however, intelligence officers of the U.S. First Marine Division estimated that 50% of all Iraqi combatants in central Iraq were foreigners.
In addition, the Kurdish Islamist militant group Ansar al-Islam controlled a small section of northern Iraq in an area outside of Saddam Hussein's control. Ansar al-Islam had been fighting against secular Kurdish forces since 2001. At the time of the invasion they fielded about 600 to 800 fighters. Ansar al-Islam was led by the Jordanian-born militant Abu Musab al-Zarqawi, who would later become an important leader in the Iraqi insurgency. Ansar al-Islam was driven out of Iraq in late March by a joint American-Kurdish force during Operation Viking Hammer.
2003 invasion of Iraq