The review was prompted by the subsuming of McCain's incumbent agency, D'Arcy, into Leo Burnett, which handles advertising for the rival food giant HJ Heinz.
TBWA will be responsible for creating advertising across the entire McCain portfolio, including the Vibes hot crisp product, which was most recently handled by Campbell Doyle Dye. CDD opted not to pitch for the centralised account, citing cultural differences with McCain.
The client is believed to have been seeking more upbeat advertising to push its product range, which includes chips, potato specialities including hash browns and savoury wedges, and fast-food products such as Micro Pizza and Micro Chips.
Recent ad campaigns from D'Arcy have focused on the ease with which the meals can be prepared. The TV work for McCain chips showed two Welsh schoolgirls debating whether they preferred the product to their own father.
McCain claims to be the leading manufacturer of chips in the UK, with one in three chips consumed coming from its factories. The chip category is the biggest single frozen-food sector in the UK, with 952,700 tons of frozen potato consumed in 2000.
The company is, however, keen to diversify its range of products and last month acquired Belleisle Foods, a frozen Chinese food manufacturer in the US.
The media account, which is held by PHD Compass, is unaffected by the review.
Trevor Beattie, the chairman and executive creative director at TBWA, said: "Everyone loves McCain. It's a bit of a British institution."