The boxing icon, who had been battling Parkinson's disease for decades, passed away in hospital. He was admitted after experiencing respiratory problems.
Boxing legend Muhammad Ali died on Friday at a hospital in Phoenix, USA where he had been admitted earlier this week suffering from respiratory problems.
An icon of the 20th century, the 74-year-old former heavyweight champion had been battling Parkinson's disease for decades after a glittering boxing career which made him the most recognisable figures in the world.
"After a 32-year battle with Parkinson's disease, Muhammad Ali has passed away at the age of 74. The three-time World Heavyweight Champion boxer died this evening," Bob Gunnell, a family spokesman, said.
A funeral will be held on Wednesday in Ali's hometown of Louisville, Kentucky. The city plans a memorial service Saturday.
"It's a sad day for life, man. I loved Muhammad Ali, he was my friend. Ali will never die," Don King, who promoted some of Ali's biggest fights, told The Associated Press early Saturday.
"Like Martin Luther King his spirit will live on, he stood for the world."
The news broke and within minutes began trending on Twitter.