The agency is now the only remaining shop in negotiations with the children's toys retailer, at the end of a pitch process that has been ongoing for more than five months.
Karmarama is set to work on a number of TV ad campaigns for the brand, including its Christmas campaign.
The agency will work closely with Partners Andrews Aldridge, which looks after the Early Learning Centre's DM business, and Inbox, which was appointed last year to the brand's eCRM account.
Hurrell Moseley Dawson & Grimmer has created the majority of the advertising for the Early Learning Centre since winning the business from United London in May 2007.
However, the agency did not create any new campaigns for the brand in 2008.
Instead, the Early Learning Centre has focused more on its digital activity, recently handing Archibald Ingall Stretton a brief to create an "inspiration centre" that features play ideas for parents and special product offers.
Earlier this year, Mothercare plc, the group that bought the Early Learning Centre for £85 million in 2007, also called a pitch for its Mothercare brand. The account was awarded to Bartle Bogle Hegarty in May.