The agency saw off competition from the incumbent, Phillipson Ward Longworth Camponi, HHCL/Red Cell and Farm in a pitch run through the AAR.
It will now develop an integrated advertising campaign to raise awareness of Sky Bet's interactive TV betting services by highlighting the added excitement for Sky digital viewers who use their remote control to place a bet while watching live sport.
The Mother partner Stef Calcraft said: "Sky Bet is hugely ambitious and has a great product. It is also a tight-knit team and wants to shake things up, which makes it a perfect fit with Mother.
"I'm backing everybody involved to create something special."
The campaign, which will break later this year, will mark the first time that Sky Bet has promoted the benefits of interactive TV betting.
The real-time nature of the gaming allows viewers to place a stake on a range of possibilities as they happen.
In addition to gambling through the television, Sky Bet operates similar services over the telephone, WAP and the internet. Sky Bet more than doubled its revenues to £91 million in the six months to 31 December 2003.
Nick Rust, the managing director of Sky Bet, said: "We have big plans for Sky Bet and interactive TV will be a key factor in our future growth.
"We are very much looking forward to working with Mother to drive awareness and usage of Sky Bet's interactive service."
The pitch is not thought to affect media planning and buying, which is held by Universal McCann.