The review, which began in May, was handled by ISBA.
Hovis had previously worked with a number of digital agencies on an ad hoc basis and is the first time it has appointed one agency to handle all its digital activity.
Agency Republic’s appointment is effective immediately, with work expected to break towards the end of the year.
Premier Foods, the maker of brands including Mr Kipling cakes and Bisto gravy, saw sales rise 3% in the four months to April 25.
Sales in its baking division grew 6% during the period, which it largely attributed to Hovis and the £15m relaunch of the brand last year.
Earlier this year Premier Foods was rapped over claims that its relaunched Hovis bread is healthier than a bowl of cereal.
The Advertising Standards Authority subsequently banned Premier Foods from claiming that “just two slices [of Hovis] provides you with33% more wholegrain than a bowl of cereal”.
In July last year, Premier Foods introduced the “boy on the bicycle” from its iconic Seventies ad as a key part of its logo for the first time.