The agency will handle all UK advertising, which was previously worked on in the US by Hanft Raboy and Partners.
Mother has been briefed to produce a through- the-line campaign, set to break early next year, that will seek to give the dating site a mature brand positioning. It is understood that the campaign could be extended across Europe.
The pitch process, which kicked off in July, suffered some delays following the departure of Match.com's managing director, Jason Stockwood.
Stockwood left the company following a three-year tenure last month.
The appointment follows Match.com's acquisition by Meetic, a French online dating company, which also owns the rival site DatingDirect.