The officer woke the family up and got them out of the building.
The home did not have any smoke alarms and fire officials said they are lucky the officer saw the smoke.
"It goes back to the importance of that officer being in the right place at the right time and once again, having no working smoke detectors in the home, could have turned out a lot different than it did," said Captain John Ross, Fresno Fire Department.
No one in the family was injured but the fire did cause damage. Investigators are still working to determine what caused the fire.
The Red Cross is helping the family find a new place to stay.