Creative duties for Maestro, which was known as Switch in the UK, were previously handled by cdp-travissully. Media planning and buying was with Carat.
The move strengthens the financial services company's ties with the Interpublic agencies, which currently handle creative and media duties for its main credit-card brand.
The appointment will see the two agencies develop a UK brand campaign for Maestro, with the aim of expanding use of the card across the retail sector.
In 2004, cdp-travissully created an £8 million campaign in which the animated Switch and Maestro penguins from previous ads were married to highlight the change to the Maestro name.
Stephen Whyte, the McCann Erickson chief executive, commented: "We are proud and excited to partner Maestro as new technologies are developed for the increasingly cashless world."
Andy Jones, the Universal McCann joint chief executive, said: "The Maestro debit card business is a fantastic challenge to be presented with and this win is a strong endorsement of all the high calibre work the Universal McCann and McCann Erickson teams have delivered for the MasterCard credit card business in recent years."