The agency triumphed against WCRS in the final stage of the five-month review. MCBD was appointed in early November.
McCann is the only incumbent agency to have kept its place on the roster, after CHI & Partners, Delaney Lund Knox Warren & Partners and Publicis all failed to make it on to the shortlist.
It is understood that work from both MCBD and McCann on the Hovis brand will now go into research, after which a final decision will be made about the split of business between the two.
McCann previously handled the Mr Kipling, Cadbury cakes, Sharwoods and Bisto brands.
Premier Foods has expanded rapidly over recent years. The company acquired Campbell's in 2006, adding the Oxo, Batchelors and Homepride brands to its portfolio.
In March this year, it completed the £1.2 billion acquisition of RHM, bringing Hovis, Bisto and Mr Kipling into the fold. Other brands up for grabs include Ambrosia, Loyd Grossman and Branston.