During the Iran–Iraq War (1980–1988), Iraq engaged in chemical warfare against Iran on multiple occasions, including more than 30 targeted attacks on Iranian civilians. The Iraqi chemical weapons program, which had been active since the 1970s, was aimed at regulated offensive use, as evidenced in the chemical attacks against Iraqi Kurds as part of the Anfal campaign in the late 1980s. The Iraqis had also utilized chemical weapons against Iranian hospitals and medical centres. According to a 2002 article in the American newspaper The Star-Ledger, 20,000 Iranian soldiers and combat medics were killed on the spot by nerve gas. As of 2002, 5,000 of the 80,000 survivors continue to seek regular medical treatment, while 1,000 are hospital inpatients. Though the use of chemical weapons in international armed conflict was banned under the Geneva Protocol, much of the international community remained indifferent to the attacks; Iraq's military campaign in Iran was supported by the United States and the Soviet Union, both of whom had sought to contain Iranian influence after the Islamic Revolution of 1979.

The Iran–Iraq War, also known as the First Gulf War, was an armed conflict between Iran and Iraq that lasted from September 1980 to August 1988. Active hostilities began with the Iraqi invasion of Iran and lasted for eight years, until the acceptance of United Nations Security Council Resolution 598 by both sides. Iraq's primary rationale for the attack against Iran cited the need to prevent Ruhollah Khomeini—who had spearheaded the Iranian Revolution in 1979—from exporting the new Iranian ideology to Iraq. There were also fears among the Iraqi leadership of Saddam Hussein that Iran, a theocratic state with a population predominantly composed of Shia Muslims, would exploit sectarian tensions in Iraq by rallying Iraq's Shia majority against the Baʽathist government, which was officially secular and dominated by Sunni Muslims. Iraq also wished to replace Iran as the power player in the Persian Gulf, which was not seen as an achievable objective prior to the Islamic Revolution because of Pahlavi Iran's economic and military superiority as well as its close relationships with the United States and Israel.