The Gym Group said its branch at the Bill Shankly Kop end of Deepdale stadium will close at noon on Friday, July 29.
There are no plans to open another gym in the city, it said. Instead, members are invited to transfer to its new 24-hour gym in Leyland, which opened in March.
A post on its Facebook page says: “We’re sad to say that The Gym Group Preston will be permanently closing on Friday, July 29 at 12 noon.
"Our members are incredibly important to us, and we know that the closure will be very disappointing news to many. It is not a decision we have taken lightly.
"Members can continue to access the gym as normal until the closing date.
"We will be contacting members via email with further details on payments and how they can continue their fitness journey with us.”
It has not said why its Preston branch is being axed. Despite the closure, the business says it still has plans to open more gyms elsewhere in the UK.
Oliver Tester, head of property acquisitions, said: “Sadly, The Gym Group Preston will be closing at the end of the July.
"All members will be able to transfer their memberships to our gym in Leyland, providing them with access to our high-quality equipment and trainers and allowing them to continue their fitness journeys with us.
"We remain focused on executing against our growth strategy – we are targeting 300+ sites by 2025, further delivering on our goal of breaking down barriers to fitness for all.”