The 37-year-old man fell from an air ambulance, which was taking him off a Norwegian oil rig, reported the Aftonbladet newspaper.
The Swede, who had reported feeling extremely ill, was in the process of being airlifted from a Statoil rig in the North Sea.
Via an emergency exit, the man fell to the waters below at around 8.45 on Wednesday morning, and was found dead around an hour later.
The man's family has been notified.
Details remain unclear as to how the man fell from the helicopter, but Norwegian police do not suspect any crime.