Aleksanyan, 36, who has been accused of embezzlement and money laundering, suffers from both AIDS and cancer. The decision to move him was made following demands from lawyers and former colleagues that the businessman be released. The prosecution earlier insisted he should undergo medical treatment in jail.
"The medical service of the Moscow department of the Federal Penitentiary Service decided to put him in hospital in line with expert recommendations," the service said. "The decision is currently being coordinated with Moscow's health department."
The prosecution accuses Aleksanyan of embezzling over 8 billion rubles ($329 million) from former Yukos production unit Tomskneft, as well as shares worth over 12 billion rubles ($493 million) from other oil companies, and of laundering stolen assets.
Aleksanyan, who looked gaunt and tired in court on Wednesday, earlier claimed that he had not received any medical treatment because he had refused to help authorities make the case for new charges against his former boss at Yukos, Mikhail Khodorkovsky.
The former Yukos CEO, who is facing new fraud charges, declared a hunger strike in his Siberian jail last week, demanding that Aleksanyan receive medical treatment. Khodorkovsky's lawyer, Vadim Klyuvgant, said on Thursday his client would call off his hunger strike as soon as he receives official confirmation that his former colleague has been moved to a clinic.
Khodorkovsky, 44, is currently serving an eight-year prison term for fraud and tax evasion. He has consistently maintained his innocence, saying that his imprisonment is a direct result of his support for Russia's tiny pro-Western opposition.
Once Russia's largest oil producer, Yukos collapsed after claims of tax evasion, which led to the company being broken up and sold off to meet creditor claims. The bulk of its assets were bought through liquidation auctions by government-controlled oil company Rosneft.
Khodorkovsky's business partner Platon Lebedev, also serving eight years for fraud and tax evasion, said last week in a Chita court that he was ready to plead guilty to new charges if it would help Aleksanyan get medical treatment.
The latest charges against Khodorkovsky and Lebedev, who were convicted in 2005, include stealing government shares, illegal oil trading, and laundering $25 billion earned from oil sales in 1998-2004. Both businessmen have denied the allegations, calling them politically motivated.
