U.S. commanders fear trouble if those coming back find others are occupying their former homes, The New York Times reported.
"All these guys coming back are probably going to find somebody else living in their house," said Col. William Rapp, a senior aide to Gen. David Petraeus, the U.S. commander in Iraq.
Rupp said U.S. officials have been "pleading" with the government to work out a policy.
The Iraqis from Syria were escorted to Baghdad in a convoy. Most said they came back to Iraq voluntarily, although some said they were unable to find work in Syria and were running out of money.
The government has named Ahmed Chalabi to determine how to re-integrate refugees. He said he has been focusing on building more housing, the Times reported.