The anti-poverty charity said it has a goal of saving £7 million a year as part of it new global strategy called Standing Together and that "political uncertainty and a tough environment for unrestricted fundraising" means some staff may have to be made redundant.
Christian Aid will withdraw from 12 countries in order to reduce unrestricted spending from £47m to £40m a year.
The countries the charity is leaving are Angola, Egypt, Zambia, Mali, South Africa, Ghana, the Philippines, Nepal, Bolivia, Colombia, Guatemala and El Salvador.
Amanda Mukwashi, chief executive of Christian Aid, said: "After careful consideration of every piece of work Christian Aid does, the senior leadership and trustees have made the difficult decision to exit from some countries and instead, in some cases, work regionally to have greater impact.
The charity said it will still be working in 15 other countries and the new strategy will help it to be "more focused and deepen its interventions in fewer countries and to do so as good stewards living within our means".
The charity employs around 1,100 people. Half the jobs at risk are in the UK.