Leader of Ipswich Borough Council visited the Two Rivers Medical Centre site in Woodbridge Road East on Wednesday to mark the milestone.
The centre will bring together the merged Lattice Barn and Woodbridge Road surgeries and will serve more than 25,000 patients in north-east Ipswich after it is finished this summer.
Dr Jonathan Knight, one of the GPs who work at the centre, said: “It has taken many years of hard work for us to get to this point.
“We are grateful to all the individuals from many different organisations that have supported this project.
“Our staff and patients must be given huge credit for managing with sub-standard facilities for so many years; now we are close to realising a 21st century facility from which we can provide care for generations to come.”