City police spokesman William Kaempffer said a man in his 20s was found unresponsive at the festival Friday afternoon.
The man was transported to an area hospital where he was pronounced dead, Kaempffer said.
The death is under investigation but police believe it to be the result of "an apparent drug overdose," Kaempffer said.
City police were in the festival campgrounds speaking to patrons in the area of Main Beach, where Barnum Dyke meets Soundview Drive.
The man's identity was not released pending notification of his next of kin, Kaempffer said.