Barnardo's and Unison are close to signing a recognition agreement for staff at the children's charity, which should be announced in mid-May.
The agreement will be one of the biggest in the voluntary sector, and follows a vote for recognition by 76 per cent of the charity's staff, who voted last spring.
Barnardo's, which has 5,800 employees, will announce the agreement jointly with the union after a meeting of its council next month.
Barnardo's finance and corporate services director, Ian Theodoreson, said recognition would improve relations between management and staff.
Employment analysts Income Data Services reported last month that under a quarter of charity staff were members of a union, and 41 per cent of organisations had full recognition agreements.