The new Swindon site opens in April and will receive daily deliveries to maintain a stock of over 1,000 vehicles.
The showroom covers 123,000 sq ft, within the eight-acre former EMI CD manufacturing site.
A Car Shop Megastore’s spokesperson said: “We’re delighted to be opening our fourth branch in Swindon and putting to use such a landmark building that has stood empty for four years.
“We’ll be the only car supermarket within one hour’s drive time of Swindon, offering a selection of family cars, MPVs, sports cars, prestige cars and vans.”
The group hopes to bring about 100 jobs to the area and will also contract out work to local car bodywork companies.
The launch of the new Swindon site is scheduled for early April.