The lucky ones move in with relatives; the poorest sleep under bridges. Others find themselves crammed into the old Palestinian refugee camps of south Beirut.
In a region where one upheaval succeeds another, the casualties of an earlier "catastrophe" in the eyes of Arabs - the birth of Israel 65 years ago - are now living alongside the fugitives of today's calamity in Syria.
This remorseless flow of refugees into neighbouring countries means talk of a "Syrian" civil war no longer makes sense. This conflict has spread beyond President Bashar al-Assad's blood-soaked domain to become a crisis for the entire Middle East.
The numbers are staggering. At least 8000 refugees enter Lebanon every day, swelling the country's four million population by a quarter in just two years; 720,000 are registered, but there are probably another 300,000.
Jordan and Turkey have 500,000 registered refugees each; even Iraq is in the unusual position of being a safe place, hosting 170,000 Syrians.