The agency won the business after a competitive pitch against three other agencies, but this appointment does not affect the position of EHS Brann, which handles the charity's direct mail business.
Partners Andrews Aldridge will create a television campaign to bring in new donors to the charity. Its work is likely to run on daytime and satellite television.
The charity has never before used DRTV but in 1997 ran brand TV advertising through Ogilvy & Mather. Last year it spent £1 million on press activity through Bartle Bogle Hegarty.
Andrew Nebel, Barnardo's director of marketing and communications, said: "Our goal is to ensure that we continue to have regular committed donors and we shall be working with our new partners on putting together an attractive package. This is a new area for Barnardo's and one which will provide the opportunity for us to get our message directly across to people in their homes."
Barnardo's will run two phases of DRTV advertising this year.
Steve Aldridge, a creative partner at Partners Andrews Aldridge, said: "The more you learn about Barnardo's the more respect you have for what they do. Taking the brand on to television to connect with an audience that is willing to give is a fantastic opportunity."
Media for Barnardo's is handled by John Ayling & Associates.