Whitewater, which handles mailing campaigns for the RSPB, RNLI and Emmaus UK's fellow homeless charity Shelter, will handle mailing communications for the organisation's donor campaigns.
Emmaus UK said it had chosen Whitewater because of its campaign success with other not-for- profit organisations. The charity said it was undergoing a new phase of growth, which Whitewater would be supporting, as it aims to open a further seven Emmaus Communities by 2010.
Steve Andrews, managing director at Whitewater, said: "Emmaus have a powerful model to help homeless people rebuild their self-confidence, self-esteem and skills. Donors will love it."
Kieran Kettleton, director of fundraising at Emmaus UK, added: "We decided to go ahead with Whitewater, an agency well known for achieving excellent results for a range of clients in the not- for-profit sector."