The Publicis agency, which won the £15m Premier business in December last year, has now wrested the £11m RHM business from Interpublic's Universal McCann. Premier Foods bought RHM for £1.2bn in March.
As a result of the win, MediaVest has captured brands including Hovis, Sharwood's and Mr Kipling.
Premier Foods was formerly part of the Hicks, Muse, Tate & Furst Group
and floated on the stock market in 2004.
In 2006, it bought the Campbell Soup Company, before acquiring RHM.