Buddy, a chocolate Labrador, alerted its owner in Sacramento, California, to a fire in his home that apparently had no working smoke alarm.
The man when awakened discovered a fire burning in a bedroom at the rear of the house.
Sacramento Fire Department spokesman Roberto Padilla said fire crews were called to the home at about 6:30 pm local time on Thursday.
Padilla said the man suffered some smoke inhalation and had soot on his face.
Padilla said the man did not recall hearing a smoke alarm, and firefighters had found no evidence of a working smoke detector in the house.
He said the home suffered significant damage.