The 41-year-old was admitted on Friday after reportedly suffering from pneumonia. Hospital sources told Spanish media that Ronaldo left on Tuesday.
Ronaldo assured fans on social media on Sunday that he was fine and would soon be ready to go home after suffering "a heavy bout of flu."
Ronaldo retired from football in 2011 following a hugely successful career which featured stints at PSV Eindhoven, Barcelona, Inter Milan, AC Milan, Brazilian sides Corinthians and Cruzeiro as well as Real Madrid. He won the Ballon d'Or award for the best player in the world in 1997 and 2002.
(Reporting by Rik Sharma; editing by Clare Fallon)
