Convenience store and CTN chain Martin McColl is selling off 54 of its 1,274 stores.
Eighteen of the sites for sale are in Scotland and 16 are in the Midlands and west of England. A further 11 stores are in the north of England, with the remaining nine in the south east. Some of the sites include a post office and National Lottery terminals.
Christie & Co, which is selling the sites for Martin McColl, said the retailer wished to dispose of them because they did not fit the company's future strategy.
Although the stores had only been on sale since the beginning of this week, Christie & Co said it had been "inundated with inquiries". Most of the interest was for individual sites, although an inquiry had been made in Scotland for a group of three stores.
Martin McColl topped The Grocer's poll of the Top 50 independent retailers last month, with a turnover of £680m in 2006, ex-fuel.
Last month it revealed it was in the market to buy a rival c-store chain.