She was in charge of a staff of over 100, who work on publishing, media enquiries, public enquiries and advertising.
The director of corporate affairs Martin Kyndt is now acting head of marketing and communications.
The charity is currently assessing its communications offerings. A succession plan will be decided shortly.
Phillips had worked at the charity for thirty years, starting as the editor of Christian Aid News in 1977 when the charity’s income was less than £5 million a year. Income is now close to £100 million.
She was awarded an OBE in 2006 for services to disadvantaged people.