Investigators say the unit was engulfed in flames when crews arrived at the scene near Central Avenue and Union Hills around 1:30 a.m. Monday.
One of the two people that live in the trailer was inside at the time of the fire. He woke up, smelled the smoke and was able to get out safely.
Crews say there are no utilities being run to the unit and the occupants were using candles for light.
"This type of house is typically hard for firefighters because it's packed with a lot of goods on the inside.. so just small aisle ways to make your way through the house," explained Capt. Ken Kohler of the Phoenix Fire Department. "One firefighter fell through the floor, but we got him up safely."
No injuries were reported.