The school says the 22-year-old male student fell from Orton Hall on Wednesday night.
University spokesman Darin Watkins says the student suffered extensive injuries and was flown to Sacred Heart Medical Center in Spokane.
The student's fall was broken by trees next to the building and he landed in the grass. When emergency crews arrived, the student was conscious and talking.
WSU Police say alcohol was not a factor in the fall and no foul play is suspected.