Refugees will receive healthcare, housing and language classes for their children.
The capital now had nearly one million displaced people for an estimated total population of four to five million, it said. There are 1,930,946 internally dispaced people across the country.
“Heads of families have very often fled or joined an armed group… Violence, rape, the omniprescence of armed groups and drugs are a widespread phenomenon among the displaced,” the Red Crescent said.
“Iraq is still under foreign occupation and Iraqis continue to die in great numbers”
“The horror of daily slaughter and attacks has a serious impact on the psychological health of the women and children.”
The report offered no explanation for the sudden jump in Baghdad residents leaving their homes, but it coincided with the sixth month of a vast US military offensive, the so-called “surge”, to try to improve security there.
US claims of success in the battle against armed groups across the capital could have spurred civilians to flee during a period of relative calm.
The Iraqi Red Crescent, one of the few humanitarian organisations still active in the country, said the sectarian violence that followed the attack on the Shia shrine in Samarra in February 2006 sparked the exodus of thousands of Iraqis.
“Thousands of Shias fled Sunni zones, and vice-versa. Many Christians also left Sunni districts to go to Kurdistan” in northern Iraq, where recent Turkish and Iranian bombardments of frontier regions have also prompted thousands to flee, the group said.
“These recent events, in addition to decades of severe oppression and sanctions fractured the integrity of the civil order and society in Iraq,” the Red Crescent said.
However, the Red Crescent figures suggested that the search for shelter is not necessarily based on sectarian or ethnic criteria. Many Sunni and Shia families are reportedly seeking refuge in mixed districts.
Separately, the UN refugee agency has said that 1.4 million Iraqis have now sought refuge in Syria, with between 500,000 and 750,000 in neighbouring Jordan.
This exile is the largest population upheaval in the Middle East since the flight of the Palestinians after the creation of the state of Israel in 1948.