Former heavyweight world champion had retired from boxing in 1981 with a record 56 wins and only five losses.
Muhammad Ali, the boxing legend, has died in a hospital in the US state of Arizona.
The 74-year-old former heavyweight world champion had been hospitalized on Thursday with respiratory problems.
US media reported that the problems were complicated by his Parkinson’s disease.
Ali was born in Louisville, Kentucky, on January 17, 1942, as Cassius Marcellus Clay Jr, a name shared with a 19th century slavery abolitionist. He later changed his name after his conversion to Islam.
Ali was known globally not only for his ring career but also for his civil rights activism.
He had been hospitalized multiple times in recent years. Ali spent time in hospital in 2014 after suffering a mild case of pneumonia and again in 2015 for a urinary tract infection.