A valuation was sought for a Weston GP surgery before it was mistakenly put up for sale last week.
Graham Road Surgery was listed as an 'eight-bedroom detached house' priced at £800,000 before being removed by estate agent Saxons.
Mark Graham, chief executive of the building's owner's, For All Healthy Living CIC, said: "We were getting a valuation from an estate agent.
"He made a mistake and put it up for sale without our instruction.
"We have no intention of selling the surgery while there are patients using it."
The surgery is used by thousands of patients and welcomed those who used Clarence Park Surgery following a merger on Tuesday.
MORE: Weston doctors surgery to become nursing home?
A spokesman for Pier Health Group, which runs health services at the site, said: "It was a surprise to us to see the owners of the building, For All Healthy Living CIC, put the building up for sale on September 14 as they had not notified us of this intent."
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here