The split signals the end of a six-year relationship, during which time Mother has produced award-winning campaigns for brands including Super Noodles and Cup-a-Soup.
Campbell confirmed that it has already begun talks with other agencies about the £7 million business. Its roster agencies Young & Rubicam and Abbott Mead Vickers BBDO are expected to be in contention.
Both parties insist the break-up is amicable but Mother's Stef Calcraft admitted the partnership had come under some strain following Unilever's sale of Batchelors to Campbell two years ago.
Two years after the deal Richard Kingsbury, the marketing controller who had bought Mother's campaigns, left the new regime.
Calcraft said: "Following Campbell's purchase of Batchelors in 2001 from Unilever it has become increasingly apparent that the views of the client and the agency are too divergent and so it is with a heavy heart that we call it a day.
"Having to walk away from Super Noodles, Cup-a-Soup and Fray Bentos is one of the most difficult decisions we have ever had to make."
Tim Perman, the managing director of Campbell's Grocery Products, said: "We are disappointed as Mother has given our business terrific support over the years and made some outstanding ads.
"However, we have big plans for our brand and look forward to building on the history of great advertising we have in our portfolio."
Mother's appointment to the Batchelors account, just four months after the agency's launch, helped alter the way convenience food was viewed.
Campaigns such as "selfish" for Super Noodles turned around the company's fortunes. The successful strategy saw Mother target lads instead of mums.
Last year its "face-off" spot for Super Noodles picked up a gold at the British Television Advertising Awards, while its "marathon" spot for Cup-a-Soup took a silver award at Cannes.