Leo Burnett replaces JWT Worldwide.
The appointment follows a review, first reported in August, that the company was reviewing its ad agency roster in a bid to reduce the number of marketing communications suppliers it employs and cut costs.
Kellogg, which owns cereal brands including Kellogg’s Special K, Coco Pops and Crunchy Nut, has preciously worked with agencies including Leo Burnett, JWT and Carat.
Kellogg recently launched a £3m six-month coupon campaign aimed at driving sales to the cereal category.
The cereal maker also claims to have developed technology to stamp its logo on individual corn flakes to counter imitation cereals.
Kellogg could not comment at the time of publication, but the decision is thought to have come from Kellogg’s US headquarters in Michigan.
Leo Burnett declined to comment.