The market is home to traders including Chen’s Happy House, BangGaBangGa and Loaded Gyros.
Some customers said the closure of the street food stalls would be a “big loss”.
Regular visitor Steph Bellfield said she was disappointed to lose “a staple of mine and my colleagues’ lunchtime routine”.
Theophilus, who works nearby, said the market had become a “social hub” for him and his colleagues.
Mohammad Khan was more optimistic, saying the move could help some businesses grow.
“Everyone’s got to move on at some point. It might make them bigger and give them more customers,” he said.
The refurbishment of Piccadilly Gardens will include new lawns, more trees, a larger playground, extra CCTV and improved lighting.
A Manchester City Council spokesperson said: “We have always believed in the important role that markets can play in our city to support businesses to grow, build a loyal customer base and thrive.
“We have been in conversation with the traders for many months around the closure of the market. So, while the street food market will close at the end of October, no trader will be left without somewhere to go.”