Bol died at the University of Virginia Hospital in Charlottesville, where he was being treated for severe kidney trouble and a painful skin condition, Tom Prichard, executive director of the group Sudan Sunrise, said in an e-mail.
"Sudan and the world have lost a hero and an example for all of us," Prichard said. "Manute, we'll miss you. Our prayers and best wishes go out to all his family, and all who mourn his loss."
Bol played in the NBA with Washington, Golden State, Philadelphia and Miami, averaging 2.6 points, 4.2 rebounds and 3.3 blocks for his career. He led the league in blocks in 1985-86 with Washington (5.0 per game) and in 1988-89 with Golden State (4.3 a game).
"Manute's impact on this city, our franchise and the game of basketball cannot be put into words," 76ers president and general manager Ed Stefanski said in a statement. "He ... was continually giving of himself through his generosity and humanitarian efforts in order to make the world around him a much better place, for which he will always be remembered."
Bol joined the NBA with Washington in 1985 and played three seasons there. He returned to the team briefly toward the end of his career. The Wizards lauded him as a "true humanitarian and an ambassador for the sport of basketball."
"Despite his accomplishments on the court, his lasting legacy will be the tireless work and causes he promoted in his native Sudan and the cities in which he played," the club said in a statement.
After the NBA, Bol worked closely as an advisory board member of Sudan Sunrise, which promotes reconciliation in Sudan. .
Bol was hospitalized in mid-May during a stopover in Washington after returning to the United States from Sudan. Prichard said then that Bol was in Sudan to help build a school in conjunction with Sudan Sunrise but stayed longer than anticipated after the president of southern Sudan asked him to make election appearances and use his influence to counter corruption in the county.
He said Bol had undergone three dialysis treatments and developed Stevens-Johnson Syndrome, a condition that caused him to lose patches of skin. Prichard said the skin around Bol's mouth was so sore he went 11 days without eating and could barely talk.
Prichard said it's believed Bol contracted the skin disease as a reaction to kidney medication he took while in Africa.
Janis Ricker, operations manager of Sudan Sunrise, said Saturday the organization will continue its work building the school in Bol's home village in southern Sudan. She said Bol's goal was to build 41 schools throughout Sudan.