McCartney who was performing to 67,000 fans fell, face first, as she left the stage in Morumbi Stadium in Sao Paulo.
The Daily Mail newspaper is reporting that the 67-year-old rocker tripped over a bunch of cables and fell to the floor before jumping up again.
An audience member caught the fall on camera.
Fans were initially in shock when they saw the performer fall but cheered loudly when he got up again.
He told the crowd: "I love South American audiences.
"I always think I have Latin blood because I connect so strongly with their love of music and their love of rhythm and their love of melody, so I always feel like I have a very big bond with South American people and Latin people in general."