Former Fifa president Joao Havelange has been admitted to hospital in Brazil with a lung infection.
Doctors say Mr Havelange, who is 98, is in a stable condition.
He was president of football's governing body from 1974 to 1998 and remained as Fifa's honorary president until last year.
He resigned following an investigation into allegations that he had accepted bribes to grant lucrative World Cup contracts to marketing company ISL.
Mr Havelange has been in hospital in Rio de Janeiro since Wednesday, but the information has only now been confirmed.
During his six terms in office, Mr Havelange oversaw the transformation of football into a global, lucrative sport.
He is credited with encouraging the development of the sport in new markets, such as Africa, Asia and the United States.
Before that, he led Brazilian football in its most successful period.
Mr Havelange was president of the Brazilian football confederation (CBF) when the country won its first three World Cups in 1958, 1962 and 1970.
His son-in-law, Ricardo Teixeira, led Brazilian football to new glories, with two more World Cup trophies in 1994 and 2002.
But Mr Teixeira also faced allegations of irregularities, which he denied, and resigned "for medical reasons" in 2013 after 23 years as CBF president.