About 150 Iraqis, many of them recipients of humanitarian aid, rallied in front of the Baghdad offices of CARE International to demand the release of Dublin-born hostage Ms Margaret Hassan.
Ms Hassan, the Iraq director of CARE International, was abducted last Tuesday on her way to work at the organisation's west Baghdad headquarters.
The 59-year-old, who holds British, Irish and Iraqi citizenship, is married to an Iraqi and has spent nearly half her life in humanitarian work in Iraq.
"We demand the release of this woman who took part and exerted painstaking efforts in reconstructing Ibn al-Qif Hospital for spinal diseases," said Abbas Mahdi al-Musawi (25) a wheelchair-bound patient who joined the protest. "She helped provide the hospital with wheelchairs for the patients and medical aid."
Nasrat al-Asadi, a teacher at an Iraqi school for the deaf, brought about 30 pupils to the demonstration because of Hassan's efforts on behalf of hearing-impaired Iraqis.
"They all love her," al-Asadi said. "She helped them with hearing aides besides reconstructing the institute."
Many protesters carried pictures of Hassan and banners calling for the release of "Mama Margaret."
No group has acknowledged holding her but a videotape broadcast last week by Al-Jazeera television showed a terrified Ms Hassan begging for her life, pleading with British Prime Minister Tony Blair to remove British soldiers from Iraq.
The Taoiseach issued a statement to Al Jazeera television on Friday evening calling for her release.