The appointment follows a pitch against the incumbent, Carat, Media Planning Group and OMD.
MEC was appointed as part of a rolling, market-by-market international pitch process, which is scheduled to end in 2008. Last week, MPG was appointed to handle Danone's US media account.
Gayle Noah, the UK media manager at Danone, said: "All four agencies exhibited a high level of competence and professionalism, but it was MEC that demonstrated a deep understanding of our brands, creativity and strategic insight into how we can navigate the challenges ahead."
Tom George, the managing director at MEC, said: "The opportunity to work with some of the biggest and best brands in the sector is really exciting and we can't wait to get started."