OMD won the account, which is expected to be worth about $200 million, following a pitch against the incumbent, Mindshare.
OMD, which also handles Pepsi in the US, will also deal with all digital media and buying for the brand.
Last year, Pepsi announced plans to invest almost $1 billion in China by 2012. The planned investment includes becoming the exclusive non-alcoholic drink and snack partner for the USA Pavilion at the 2010 Shanghai World Expo.