The first suspected polio case in 14 years in the country was confirmed by Iraq's health ministry. It said the case could have originated in neighboring Syria where confirmed cases have sparked a region-wide alert.
The suspected case was found in a young boy in Bab al-Sham near Baghdad, ministry spokesman Ziad Tariq told AFP.
He said the case was not yet confirmed and that samples had been sent to the United States for further testing, with results expected on Sunday.
If confirmed, it would be Iraq's first case of polio since 2000.
"We suspect the case originated in Syria," Tariq said. "We are afraid of that, we have thousands of refugees from Syria, and the health situation is complicated because Anbar is bordering Syria."
Anbar, a predominantly Sunni province in western Iraq, has been long been a source of unrest in Iraq.
In early January, anti-government fighters took control of all of the Anbar city of Fallujah, and parts of the provincial capital Ramadi, some of which they still hold.
Late last year, the UN confirmed that at least 17 children in war-wracked Syria had been paralysed by polio, in the country's first cases of the disease since 1999.
Fifteen of the cases were in the eastern province of Deir Ezzor, large swathes of which are under rebel control.
The outbreak in the midst of Syria's three-year-old civil war prompted the World Health Organisation and UN childrens' agency UNICEF to launch a vaccination campaign for 23 million children across the Middle East, which got under way in earnest this month.
Tariq said a vaccination campaign was already under way in Iraq and would run until April 6, over and above routine childhood vaccinations.