Iran had created the SDC in 1980 to undertake what the Iranians called Jange Tahmili, or the imposed war. Iran launched a counteroffensive in January 1981. Both the volunteers and the regular armed forces were eager to fight, the latter seeing an opportunity to regain prestige lost because of their association with the shah's regime. Iran's first major counterattack failed, however, for political and military reasons. President Bani Sadr was engaged in a power struggle with key religious figures and eager to gain political support among the armed forces by direct involvement in military operations. Lacking military expertise, he initiated a premature attack by three regular armored regiments without the assistance of the Pasdaran units. He also failed to take into account that the ground near Susangerd, muddied by the preceding rainy season, would make resupply difficult. As a result of his tactical decision making, the Iranian forces were surrounded on three sides. In a long exchange of fire, many Iranian armored vehicles were destroyed or had to be abandoned because they were either stuck in the mud or needed minor repairs. Fortunately for Iran, however, the Iraqi forces failed to follow up with another attack.

After Bani Sadr was ousted as president and commander in chief, Iran gained its first major victory, when, as a result of Khomeini's initiative, the army and Pasdaran suppressed their rivalry and cooperated to force Baghdad to lift its long siege of Abadan in September 1981. Iranian forces also defeated Iraq in the Qasr-e Shirin area in December 1981 and January 1982. The Iraqi armed forces were hampered by their unwillingness to sustain a high casualty rate and therefore refused to initiate a new offensive.

In March 1982, Tehran launched a major offensive called "Undeniable Victory." Its forces broke the Iraqi line near Susangerd, separating Iraqi units in northern and southern Khuzestan. Within a week, they succeeded in destroying a large part of three Iraqi divisions. This operation, another combined effort of the army, Pasdaran, and Basij, was a turning point in the war because the strategic initiative shifted from Iraq to Iran. In May 1982, Iranian units finally regained Khorramshahr, but with high casualties. After this victory, the Iranians maintained the pressure on the remaining Iraqi forces, and President Saddam Husayn announced that the Iraqi units would withdraw from Iranian territory.

Data as of December 1987