Hoyland market is struggling to pull in the punters, leading to fears it might fold.
Traders said customer numbers had fallen and high rents meant there were also fewer stallholders.
Geoff Crossley has sold cleaning products and toiletries on the market for 43 years.
He said every stall used to be 'jam-packed full' but now about half as many people come to the market.
"There's a big danger the market could go. I don't want it to. These lads that are on here they're regulars and they all think the same."
Geoff added the new Tesco planned on Market Street would take trade from the market and mean people would not need to come into the town centre.
Andy Goldthorpe works at Hall's Green Grocers and says people in the town do not support the market. He said the shop has been next to the stalls for 40 years and fewer people come to the market.
Andy said the 'entire heart of the town' has been ripped out with the demolition of the Factory Outlet and the building of the new health centre. He said the outlet shop brought people into the town but now there is nothing to attract them.
The market is held on Tuesday, Thursday and Saturday and Andy said the second hand stall on Thursday is well attended because people do not have a lot of money.
But he said shopping habits have changed with more people buying through supermarkets online.
However Anne Untisz, town centre services manager, said Hoyland market was doing well compared to other markets in the borough.