The fire broke out just after nine last night in a building near Fresno and T Street near Community Regional Medical Center.
Four people were displaced by the fire. The building has businesses on the ground floor with apartments above.
Firefighters say they don't have an exact cause for the fire, but it appears to have started near an oven that was being cleaned in one of the apartments. They were able to contain the fire to just that single unit, but the fire did spread to the attic above the other units.
"The roof line has been altered a couple of times so the fires have been stuck in between the layers and its very difficult to put out. So the majority of the fire is under control but there's still firefighting in the back," said Fresno Fire Dept. Deputy Chief Michael Despain.
No one was injured in the fire and the Red Cross is assisting those who have been displaced.