Jasper Conran, Clare Gerbrands and the late Isabella Blow at the launch.
The monthly experiment that was launched with help from fashion designer Jasper Conran and the late style icon Isabella Blow in July 1999 has turned into a weekly date in the social calendar for thousands of shoppers.
It has also helped to breath new life into the fortunes of dozens of local food and drink producers.
On Saturday a limited edition series of market anniversary postcards and shopping bags will be available to the first few hundred customers.
New banners proclaiming all that's good about the market will adorn Cornhill, ahead of a cake cutting ceremony by Guardian food critic Matthew Fort and civic leaders at 11am.
Organiser Clare Gerbrands said she never dreamed what a runaway success the market would be. It was launched on a monthly basis after a suggestion from Stroud District Council and then went fortnightly after only six months. In August 2006 it became a weekly fixture.
"I never imagined it would capture people's imaginations the way it has," said Clare, 45, who also runs the Made in Stroud shop in Kendrick Street.
"The council asked us to run it and include local farmers. We now regularly attract 50 or more stallholders, all selling their own home-grown and home-made produce."
She added: "Thousands of customers flock to the market every week and it is now the biggest farmers' market in the South West, bringing much trade into the town centre and contributing to Stroud's renaissance as a successful market town, even in difficult economic times."
The market was originally funded by grants from the district and town councils but now pays its own way. It is one of only a few outside London to run weekly and independently.
The new banners, postcards and bags were designed by artist/illustrator Simon Watkins, aka Vietnam the Movie, and Clare.
For the future Clare, who was quickly joined in running the market by her 46-year-old husband Gerb, would like to see more community involvement.
"I'd like Stroud Farmers' Market to become a destination for visitors to the town, to make it somewhere people drop into when on a tour of the Cotswolds," she said.
Stroud Farmers' Market has enjoyed celebrity visitors as diverse as internationally-renowned textile designer Cath Kidston and TV's motorcycling chefs the Hairy Bikers. It has been used as a film location by BBC One's Blue Peter and celebrity chef Rick Stein's Food Heroes and it has helped guest charity stalls raise thousands.
■ Comment, page 6
July 1999: Launched by celebrities Jasper Conran and the late Isabella Blow.
August 1999: Market expands into the streets around Cornhill square as demand for stalls grows.
December 1999: Now runs twice a month and is nicknamed "Notting Hill in wellies" by the London Evening Standard.
November 2000: Becomes the first UK farmers' market to introduce reuseable cotton bags.
March 2001: Foot and Mouth disease shuts out the farmers but the market carries on with food producers and craftspeople.
May 2001: Farm producers return.
February 2007: Stroud wins the National Farm Retail and Markets Association annual Farmers' Market of the Year award for the South West.