The telephone fundraising and donations processing functions at Kidney Research UK are to be outsourced as part of a restructure at the charity.
An employee of the charity, who asked not to be named, told Third Sector there were 29 people in the telephone fundraising department and they had been told they would all lose their jobs at the charity. The employee said its office in Huntingdon, Cambridgeshire, was to close.
A spokesman for the charity said he could not say how many staff would be affected.
"We want to observe due sensitivity to those directly affected and this must remain confidential until the process is complete," he said.
He said all the staff affected would be given the option of working for the outsourced suppliers, but was unable to confirm whether staff would automatically be transferred into the new jobs.
The restructure is expected to be completed by April.