They were called out to the Shortridge building on the Lochside Industrial Estate shortly after 04:00 on Wednesday.
They managed to save the main factory building from being destroyed but it still caused considerable damage to the premises.
A spokesman said six engines were in attendance and confirmed there were no casualties.
Police have appealed for anyone who was in the industrial estate overnight to contact them.
Sgt Amy Ritchie said: "We are currently carrying out inquiries into the cause of this serious fire and a joint investigation will take place today between the fire and rescue service and Police Scotland.
"No-one was injured in this incident, however, the damage is extensive."
Fire crews have tackled a major blaze at an industrial laundry in Dumfries.