The UN refugee agency (UNHCR) says there has been an "abject denial" around the world of the humanitarian impact of invading Iraq.
Many of the refugees need considerable support, and about a quarter of them are children who need education.
Many need food and healthcare, some need counselling because of the violence they have experienced or witnessed, while others need jobs.
"Food aid needs as well are becoming vital because the population is becoming further and further impoverished since they cannot work.
almost two million more people are displaced inside Iraq - people who have fled their homes to escape the violence.
That number, too, is steadily growing, the UN says, with some provinces feeling overwhelmed and attempting to close their boundaries to refugees from other areas.
Most of the people killed in Iraq's violence are men.
Their deaths leave households headed by women who struggle to survive the loss of the main breadwinner, says the BBC's Jill McGivering.
clipped from: news.bbc.co.uk