In Iraq and Syria, Christians have been persecuted on a large scale in the context of ongoing civil war. In March 2016, the US State Department declared that Christians, as well as Yazidis and Shiites, were victims of genocide at the hands of the Islamic State. 

In 1987, when Iraq took its most recent census, Christians made up about 8 percent of the population. About 70 percent of these Christians, in turn, are Catholic Chaldeans, with the rest divided among historic communities like the Armenian Orthodox and Assyrian Churches. Christians have been present on the Nineveh Plain for more than sixteen centuries, with some communities dating back to the second century AD. These communities have a long history of being attacked, including in the genocides against Armenians and Assyrians in the early twentieth century, in the quest of Saddam Hussein to assimilate Christians to an Arabic Iraqi nation between 1974 and 1989, and at the hands of Islamist militants in the wake of the Iraq War of 2003. The most recent violence has involved attacks on churches, sometimes during services. These forms of attack were continued and expanded by the Islamic State (IS), which had taken control of large swaths of western Iraq by summer 2014. 

Where IS has controlled Christians, it has presented them with the choice of converting to Islam, execution, exile, or paying a poll tax known as jizya (much harsher than its historic antecedent, and functioning de facto as naked extortion designed to drive Christians from the region). IS has carried out mass killings, including crucifixions. 

Historically, Christians in Syria have had a better existence, enjoying relative protection and middle- and upper-class status, though they have also experienced persecution during certain periods. In the 1920s, they made up some 30 percent of the country’s population. In the wake of uprisings against the government of President Bashar Assad in early 2011, a civil war erupted that left Christians vulnerable. They have been harshly attacked by Islamist factions among the rebels, including both IS, which established its capital in Raqqa in 2014, and the Al-Nusra Front, which was originally an offshoot of al-Qaida. These factions have treated Syrian Christians much like they have treated Iraqi Christians. 

Among Christians in Iraq, flight has been a major response. An estimated population of nearly 1.5 million Christians just prior to the U.S. invasion in 2003 dwindled to about 700,000 in 2006, and further to less than 400,000 in 2016, though these figures are uncertain and disputed. Almost no Christian has remained in IS-held territory. Most have gone to Kurdish and Shiite territory, from where they hope to return home, while others have fled to camps in Jordan, Lebanon, and Turkey. Still others have gone overseas. Those who have remained in the country have had to scale back their activities greatly, though they continue to worship and pray. Some have formed militias to reclaim their land, wealth, and communities—the Nineveh Plains Force, for instance—and in some cases, Christians fight IS alongside Kurds. Some engage in political advocacy at the United Nations and among Western governments for a safe haven or autonomous region on the Nineveh Plains; others document human rights abuses; others perform social services, like assisting other refugees. Cooperation among Christian communities is robust. 

Christians in Syria, too, have fled en masse from conflict zones, some of them migrating to Damascus and western Syria, others to camps in neighboring countries, and some to Europe. Others have chosen to remain in Syria. Populations of Christians in cities like Aleppo and Homs, both scenes of intense fighting, have been decimated, and Damascus now may have the greatest concentration of Christians among Syrian cities. Since 2011, an estimated two-thirds of Christians have left Aleppo, their population plummeting from an estimated 110,000 in 2010 to 30,000 today. Nationwide, even before the war, Christians had declined to some 5 to 6 percent of the population due to emigration and lower birth rates, but they are now estimated to make up only about 3 percent of Syria’s population. As in Iraq, some Christians have formed militias to protect their cities, while others perform social services, document human rights abuses, and forge cooperation among communities. One Jesuit priest, Paolo dall’Oglio, had run an interreligious monastery for thirty years and sought to carry out interreligious dialogue during the conflict, but he was exiled by the Government of Syria after he met with members of the opposition. After nearly a year outside the country, he returned to Syria but was kidnapped by IS and possibly executed, though his death is unconfirmed.