Firefighters responded to reports of a two-story building on fire near Alvernon and Pima St. early Sunday morning.
Tucson Fire Department says the building is located at 4000 E. Lee Street. The structure was a garage on the first floor with living quarters on the top floor.
When crews forced entry into the residence, they discovered that no one was inside.
It took 23 firefighters about 30 minutes to control the flames.
TFD says no firefighters were injured.
The cause of the fire is under investigation.