The man did not return to the surface of the river after jumping from Göta Älv bridge at 11.30pm on Saturday. He was rescued from the water by divers and taken to Sahlgrenska hospital.
Göteborgs-Posten reports that there were large numbers of people in the area for the Metaltown heavy metal festival.
Three people lined up to jump from the bridge. The first was greeted with applause as he swam to the shore after a successful jump.
The third jump was cancelled when the second volunteer failed to resurface after leaping from the bridge.