Paraguayan Leoz resigned on Tuesday citing health reasons with CONMEBOL advising FIFA on Wednesday that Figueredo, its vice-president, would see out the mandate until 2015 when an election will be held.
"Following the definitive vacancy of the presidency, the vice-president is taking on the position held until now by Dr Nicolas Leoz," CONMEBOL said.
"(Figueredo) will hold (the position) until the end of the current mandate, which will occur in May 2015."
Figueredo was president of the Uruguayan Football Association, one of the 10 members of CONMEBOL, from 1997 to 2006.
The 84-year-old Leoz, who had heart surgery for the fourth time in December, had led CONMEBOL since 1986. He also resigned from the position he had held on FIFA's executive committee since 1998.
"I still have good mental health but physically I'm often impeded," said Leoz.
CONMEBOL's executive committee will meet at the body's Asuncion headquarters on Tuesday for the formality of Figueredo's appointment but Leoz said his decision to resign was final.
"I've told (the presidents of the 10 South American member nations) that I'm no longer interested in staying on in the post," Leoz told Paraguayan Radio 780.
"It's something I'd been mulling over, discussing with my family and friends because the constant trips I make tire me... My body's not managing although my mind's good."
Leoz's resignation comes as a FIFA investigation into allegations of bribery involving its former marketing partner ISL are on the verge of being presented.
He was named in a BBC programme in 2010 as allegedly having received a kickback from ISL.
"That's an issue I have no idea about. I've not stolen so much as a cent," Leoz told the Chilean daily El Mercurio.
"Let them investigate all they want. The ISL thing was 13 years ago and is finished with," he said.
Asked about the controversial voting for the hosting of the World Cup finals in 2018, which went to Russia, and 2022, which went to Qatar, he said: "What would I ask for?
"I have nothing to do with that... I voted for Spain (for 2018) and the United States (2022)."
In May 2011, former FA chairman David Triesman, in a parliamentary inquiry into the country's failed bid for the 2018 finals, said Leoz had requested a knighthood in return for his vote - an allegation denied by CONMEBOL.
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