President Ivan Duque led tributes for the former conservative leader, who was president of the South American country from 1982 to 1986.
"I deeply regret the death of a great friend, a great Colombian, former president Belisario Betancur," Duque wrote in a message on Twitter.
"His legacy in politics, in our history, in our culture, is an example for all future generations."
Betancur was being treated in a Bogota clinic for a kidney condition. The Santa Fe Foundation clinic said in a statement that the ex-president passed away at 2:32 pm (2032 GMT).
Marta Lucia Ramirez, the country's vice president, had prematurely announced Betancur's death in a tweet the day before.
She corrected the mistake within minutes, but not before it was picked up by national media, leading to a flood of reactions from public figures.
The conservative Betancur was president when leftist M-19 guerrillas seized control of Bogota's Palace of Justice in November 1985 -- a dramatic foretaste of the violence that was to mark Colombia over the next decades.
He was the first president to summon the rebel groups that emerged in the 1960s to a dialogue with the government, assuring them he would work to achieve peace.
The main rebel group, the FARC, finally signed a peace agreement with the liberal government of Juan Manuel Santos more than 30 years later, in 2016.