MORLEY'S Kwik Save supermarket is to close on December 4, with the loss of 27 full and part-time jobs.
The store has been trading in Market Square since 1991.
The move follows a performance review in which the store was found to be failing to hit sales targets.
A spokeswoman for Somerfield said: "After the review that store in particular wasn't performing as it should have done."
She added: "We don't want to close our stores down - it's better for us to have them open - but if they're not performing to the required standards, we have to close them."
Kwik Save has been trading since 1965 but merged with Somerfield in 1998. In 2000 Somerfield said it would maintain the Kwik Save brand and announced its intention "to maintain all Kwik Save stores as discount supermarkets."
The decision comes a fortnight after Somerfield announced the acquisition of 114 Safeway stores from the Morrison group in a 260m deal.
Those affected by the closure will be offered alternative employment within the Somerfield group.
But they could face a longer journey to work - the nearest Kwik Save stores are in Pudsey and Beeston, in addition to a Somerfield store in Chapel Allerton, Leeds.
Three of the newly-acquired Safeway branches are also in the North Leeds area.
Stephen Kearns, president of Morley Chamber of Trade, did not find the closure surprising. He said: "It's a shame for the employees, but it was always going to struggle, given the proximity of Morrison's."