The fire broke out at a converted agricultural shed in the village of Eastham, on the south Shropshire border near Tenbury Wells at about 9.30am today.
Four vehicles were destroyed in the blaze, which also destroyed an adjoining stable block. No people or animals were hurt in the fire, however.
A spokeswoman for Hereford and Worcester Fire and Rescue Service said: "It was agricultural building that was being used as a workshop. The fire started as a car fire and spread to other cars in the workshop, and then to some stables at the rear.
"We sent two pumps and a water carrier, but before the pumps had got there they could see how big the fire was and requested help."
In the end fire crews from Bromyard, Cleobury Mortimer, Leintwardine and Tenbury Wells tackled the blaze along with the water carrier from Leominster, which was put out by about 1.15pm.
The 20 by 30 metre building was already well alight when crews arrived she said.
"It was a largish fire but it was quite easily contained by crews as it didn't really have anywhere to spread to," she said.
Fire officers returned to inspect the site yesterday evening.