The former Weston College building in Nailsea town centre is set to be converted into a medical centre.
Weston College has agreed to sell the building in Somerset Square to Tyntesfield Medical Group to enable it to expand its facilities.
Tyntesfield announced its plans to sell Brockway Medical Centre for housing in August last year.
More: Medical centre could close to make way for larger surgery.
The group, which serves almost 33,000 patients in Nailsea, Backwell, Tickenham and Long Ashton, wants to expand its facilities to cope with the growing population.
Lawrie Lewis, executive manager for Tyntesfield, said: "Having GP premises capable of delivering, long into the future, primary healthcare in the hearts of the communities we serve is important to the practice.
"It would prove difficult to do that by maintaining reliance upon the four sites we currently have. Brockway Medical Centre is a great building, but it has reached its limits and couldn't be expanded any further.
"We needed to find a solution which keeps our administration co-located with our main medical facilities in the town whilst freeing up space for future medical space expansion at all of our sites in Nailsea, Backwell and Long Ashton."
Tyntesfield Medical Group was formed in 2016 by the merger of Nailsea Family Practice, Nailsea and Backwell Medical Group and Long Ashton Surgery.
More: Three GP practices have merged.
Work has now begun with a firm of architects to find the best solution to remodel Weston College and Tower House Medical Centre, by joining them together to provide enhanced medical services and an administrative hub to support the group.
Dr Paul Phillips, principal and chief executive of Weston College Group, said: "We are pleased to be working with Tyntesfield Medical Group on a solution which will serve the community.
"It has taken a long time to find a suitable, committed purchaser with the right vision for the town, who can enhance services to the public."
Tyntesfield has been given planning permission to build homes on the site of Brockway Medical Centre in February this year. This will enable the group to sell the site to a developer to finance its new facilities.
Lawrie Lewis added: "I am grateful to Dr Paul Phillips and his team in working with us to reach this solution.
"We wouldn't have managed it without the college's help and the further support we are receiving from the clinical commissioning group, NHS England and other partners.
"I am sorry we have not been able to share such detail before with our patients, but we have had to tread carefully with our negotiations and progress.
"The next step is for Tyntesfield Medical Group to formally open up channels of communications with patients to discuss and consider their needs and desires for their healthcare.
"Our first public meeting will be held at 7pm on March 10 in Brockway Medical Centre."
A spokesman for Nailsea Town Council said: ""Nailsea Town Council is pleased to learn that Tyntesfield Medical Group is purchasing the Weston College building.
"The building has laid vacant for many years and it has always been the town council's hope that the site will be purchased and brought back to life to improve the look and the use of this part of our town centre.
"We wish Tyntesfield Medical Group all the best with developing the site."
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