The Co-op is planning to open 100 new food stores in 2018, creating around 1,600 jobs.
The retailer will invest more than £160m in the expansion, alongside “major makeovers” to a further 150 outlets.
More than 20 of the new stores will open in London, up to 18 in Scotland, 10 in Wales and the remainder in English cities including York, Plymouth and Bristol.
It comes after the announcement of an agreement for the Co-op to become the exclusive wholesale supplier to 2,200 Costcutter Group stores and a deal to buy Nisa Retail, which is subject to a Competition and Markets Authority approval.
Jo Whitfield, chief executive of Co-op Food, said: “The Co-op is positively responding to the changeas occurring within this dynamic sector.
“Our food business is going from strength to strength in what is clearly a challenging retail market.
“We have the ambition for our stores to be at the heart of local life, bringing communities together and offering our members and customers great quality products when and where they need them.”
Stuart Hookins, director of portfolio and development, added: “Our expansion plans for 2018 will mean that the Co-op is on track to have opened at least 100 new stores in each of three consecutive years.
“With over one million new active members joining us in the last year, we are always looking for new locations to get closer to where our members and customers live and work and to meet their shopping needs conveniently.”