They were working between the sixth and seventh floors when the collapse happened. Both fell to the ground and died on the scene, said Orange County Fire Rescue.
A third worker hung on and managed to climb to safety, suffering only minor injuries.
The accident took place at a hotel under construction near to the Walt Disney World resort in the Orlando area. Local reports say that concrete was being placed at the time of the collapse.
The Occupational Health & Safety Administration will be investigating the accident.