The helicopter crashed overnight about 13km southeast of Nasiriya, the southern Iraqi city where Italy's 3000 troops are based, Italy's military command said in a statement on Tuesday.
The cause was not immediately clear.
The deaths bring the number of Italian troops killed in the country to 24, according to the Defence Ministry.
In a separate incident, a US aircraft crash-landed in Tal Afar district, near Mosul in the north.
Al-Qaida's branch in Iraq said it shot down the aircraft but the authenticity of the statement could not be verified.
An Iraqi Air Force plane crashed northeast of Baghdad in a sandstorm on Monday, killing four US Air Force personnel and an Iraqi pilot.
The helicopter was the third aircraft to go down in Iraq in a week.
There are around 3000 Italian
troops in Iraq
More than a dozen US helicopters have been brought down in Iraq over the past two years by hostile ground fire, bad weather or mechanical problems.
Meanwhile, in Baghdad Iraqi Prime Minister Ibrahim al-Jaafari unveiled his new government's political programme aimed at building a federal system in the country.
"The political programme of the interim government set up following elections has the objective of building a federal, pluralist Iraq while respecting human rights and public freedoms," he said on Tuesday.
Foreign policy will be based on "reinforcing the unity of Iraq and the integrity of its territory", as well as on mutual respect for and non-inteference in the affairs of its neighbours.
The Iraqi army, al-Jaafari said, will reflect the country's ethnic mosaic.
"In order to accelerate a return to stability, the government will allocate sufficient funds to relaunch the intelligence and national defence services," he said.
Security is a vital issue for the new government in Iraq, which has witnessed a sharp escalation in attacks since the new cabinet was sworn in at the beginning of May, with about 700 people killed this month.
Al-Jaafari: New Iraq will respect
human rights and public liberties
In other news, Iraqi President Jalal Talabani has said that authorities expect to put Saddam Hussein on trial in the next two months.
In an interview with CNN on Tuesday, Talabani said that "the court of Iraq will decide the future of Saddam Hussein", and that there is a strong public desire for him to be executed if convicted.
"Saddam Hussein is a war criminal," Talabani said, noting that he had committed "crimes against Iraqi people" in Kurdistan as well as Shia areas of southern Iraq and in Baghdad.
Saddam is expected to deny charges that he was responsible for the deaths of hundreds of thousands of Iraqis and non-Iraqis.
He is expected to argue that his campaigns against the Iranians, Kuwaitis and Iraqi Shias and Kurds were justified in the interests of preserving Iraq's territorial integrity and sovereignty.
In other developments, the governor of western Iraq's volatile Anbar province has been killed during clashes between US forces and anti-US fighters who abducted him.
Aljazeera has reported quoting the Iraqi government that four other bodies have been found along with that of Raja Nawaf Farhan al-Mahallawi.
Iraqi government spokesman Laith Kuba said on Tuesday that al-Mahallawi was killed by rubble when the house where he was being held became the scene of a fierce battle between US forces and foreign fighters on Sunday.
Saddam Hussein may be put on
trial in the next two months
Kuba said al-Mahalawi had never been released, as his family thought, but had instead been handed from one kidnappers' cell to another.
Aljazeera reports that in Baquba, two Iraqi soldiers have been killed and nine others wounded after a booby-trapped truck exploded.
The Jamaat Jaish Ansar al-Sunna group has claimed responsibility for the attack in a statement whose authenticity could not be verified.