The OCI president has been placed on house arrest while investigations continue in Brazil
Pat Hickey has been released from a Brazilian jail on house arrest.
In a statement, Mr Hickey confirmed he had been released from the police detention system.
He said: "I will now stay in Rio and my lawyers will proceed to have the charges laid against me set aside as there is no substantive proof of any wrong doing on my part.
"I would like to thank the prison authorities for their kindness they have shown to me. Due to my medical condition, I will be making no further statements," he added.
A judge in Rio ordered his release from Bangu Prison yesterday.
It was decided that placing Mr Hickey under house arrest would not cause any risk to public order, or undermine the criminal investigation against him.
Judge Fernando Antonio de Almeida cited concerns over Mr Hickey's health in court documents, agreeing to grant him bail.
The judge further noted that, where possible, the law should be interpreted in favour of the accused.
It is understood that he has now left Bangu Prison in a car with blacked out windows.
Mr Hickey, who has temporarily stepped aside as president of the Olympic Council of Ireland (OCI), was arrested on August 17th in connection with the alleged illegal resale of Rio 2016 tickets.
The 71-year-old denies any wrongdoing.
In a statement, the OCI welcomed Mr Hickey's release.
They added: "The OCI also welcomes the news that three OCI officials are due to have their passports returned over the coming days and we look forward to welcoming Kevin Kilty, Stephen Martin and Dermot Henihan home shortly."
Separately, acting President of the European Olympic Committees (EOC), Mr Janez Kocijančič, said: “The EOC welcomes the news that Patrick Hickey has been released from preventative custody in Bangu maximum-security prison. We believe this was the correct decision as it respects the dignity and fundamental human rights of Mr Hickey.
"The EOC respectfully requests that these rights continue to be respected, including the principle of proportionality when under criminal investigation and Mr Hickey’s presumption of innocence.
He added that the organisation's executive committee "fully respects the Brazilian judicial procedures and it is not our intention to comment on, nor question, any matter relating to a specific legal case in Brazil".
Mr Hickey's family last week said they are concerned about the manner of his arrest, his right to a fair hearing and his detention without charge.
They have also cited worries about the effects of the arrest on his health and the pre-trial disclosure of purported evidence to the media "without any right of a reply".
A solicitor for the Hickey family has claimed Brazilian police have tried to "utterly degrade" Mr Hickey.