Pat Hickey has been released from preventive custody in Rio de Janeiro after 11 nights behind bars.
A judge in Rio de Janeiro ordered the 71-year-old's release citing his "critical health" and said there were no grounds for him to remain in Bangu Prison
Judge Fernando Antonio de Almeida said his release would not present any risk to public order. Documents lodged to the court claimed Mr Hickey's health was a reason to release him.
Judge de Almeida said preventive imprisonment can only be applied when the maximum sentence for a crime exceeds four years.
"Considering all this, I revoke the preventive prison order and now he has cautionary measures replacing his detention," the judge wrote.
Mr Hickey cannot leave the country and his passports remain with the authorities.
He temporarily stood down as Olympic Council of Ireland (OCI) president after his arrest at the Windsor Marapendi Hotel on August 17.
He has been accused under Brazilian law of ticket touting, running a cartel and illicit marketing.
Brazilian police claimed he facilitated the transfer of Olympics tickets to UK-based THG via the OCI's Authorised Ticket Re-seller (ATR) Pro10. THG was restricted from selling Olympic Games tickets.
After spending a night in the Hospital Samaritano, Mr Hickey was moved to the notoriously violent, high-security Gericino Prison, known locally as Bangu, in northwest Rio, where he was held for 10 nights.
His solicitor argued that during his incarceration Mr Hickey became unwell and lost his appetite.
Meanwhile, a solicitor acting for Mr Hickey's former cellmate, Kevin Mallon (36) - the first Irishman arrested as part of the ticket touting investigation - has claimed "no crime was committed" by his client.
Mr Mallon appeared at the Sports Fans and Large Events Court in Rio yesterday.
He said he had "no comment" to make leaving the court.
Mr Mallon was arrested on August 5 - the opening day of the Olympics - and released from prison on bail over the weekend.
Police found 823 Games tickets, many of which had been issued to the OCI, in his apartment.
Mr Mallon, from Drimnagh in south Dublin, told reporters as he entered the court building: "I have no comment to make, thank you."
His solicitor, Franklin Gomes, said: "We are very happy that Mr Mallon has been released and confident that no crime has been committed."
Asked how difficult it had been to secure Mr Mallon's released on bail, Mr Gomes said: "Well, it took like 22 days to get him released so it was very, very hard to get him out of the prison."
Mr Mallon has been charged with facilitating ticket touting and criminal association.
He has also been banned from accessing or attending premises connected to the Brazilian or International Olympic Committees for the period of the Paralympic Games.
He is further banned from attending any of the stadiums or facilities where he would encounter the Games.
The ban extends to him attending the opening and closing ceremonies of the Paralympics.