Diffiniti, the Aegis Media agency, was the previous incumbent on the account but lost the business following a pitch process.
Sky launched a review in April for all its requirements across search, display, social media, affiliates and digital creative work in the UK.
MediaCom’s appointment is part of this ongoing process and Sky is expected to hire a digital creative agency and an agency to handle its search media in due course.
As well as Diffiniti, the media company’s incumbent roster included Brothers and Sisters, AKQA, Soup and Bigmouthmedia.
According to The Nielsen Company, BSkyB spent £8.2 million on digital media, excluding search, during 2009, representing an increase of 17.2 per cent when compared with 2008.
Louise Mullock, the head of online sales and marketing at BSkyB, has been co-ordinating the review.
Sky’s recent advertising activity has pushed its broadband and sports channels range. This week, it launched Sky Sports News in high definition as part of a push to win subscribers.