Chaldean Catholic officials cancelled traditional Christmas Eve midnight Masses in December because of security risks.
Chaldean Archbishop Louis Sako of Kirkuk in northern Iraq said Christians would spend Christmas in "great fear" because of the risk of new attacks.
All Masses were held in daylight hours, he said.
"Midnight Christmas Mass has been cancelled in Baghdad, Mosul and Kirkuk as a consequence of the never-ending assassinations of Christians," he said. On Oct. 31, 2010, an attack on the Syrian Catholic cathedral left 57 people dead in the Iraqi capital.
The archbishop's concerns follow a series of incidents in Kurdistan, which had been considered a safe haven for Christians.