The arson happened just before midnight at a home near Clinton and Del Mar.
The home was filled with smoke when firefighters arrived.
The family living there was able to get out safely.
Crews put out the flames in must minutes, but they say the fire caused about $50 thousand in damage.
Investigators found someone intentionally started the fire in two different rooms.
Fresno fire officials say the people renting the house were supposed to move out yesterday.
The family is now staying with relatives.
It's not clear yet if they had anything to do with the fire.