Live Nation spokesman Kristofer Akesson said the singer felt ill ahead of her concert in Stockholm on Wednesday night and that she decided in consultation with a doctor to cancel the show about an hour before she was to go on stage.
Akesson says Rihanna "is exhausted and doesn't feel well," but could not give more details.
The singer called off a concert in Malmo in southern Sweden on Monday, but was able to perform the following night in Stockholm.
Organizers are trying to arrange new dates for the shows.
