Mr Bout's lawyer cited Guantanamo Bay in arguing against extradition
Viktor Bout, the alleged Russian arms dealer, has appeared in a Thai court to fight against his extradition.
Arrested in a sting operation led by US and Thai officers in March, Mr Bout is wanted by the US to stand trial on terrorism charges.
The Thai court must decide if there is enough evidence to justify extradition.
His lawyer argues that Mr Bout would not receive a fair trial in the US, where officials say he supplied arms to dictators, al-Qaeda and the Taleban.
Mr Bout denies the charges and his defence lawyer, Chamroen Panompakakom, says he is being detained illegally.
The man dubbed the "Merchant of Death" is being held in a maximum security prison outside Bangkok and was brought to court in leg shackles.
Mr Bout allegedly agreed to supply surface-to-air missiles to US anti-drug agents posing as rebels from Colombia's left-wing Farc group, which the US considers a terrorist organisation.
He has also been charged with conspiracy to kill US officers or employees and conspiracy to acquire and use an anti-aircraft missile.
As part of his arguments against Mr Bout's extradition, his lawyer cited the example of Hambali, an Indonesian alleged to have been a key Muslim terrorist leader in South East Asia.
Hambali was captured in Thailand in 2003, and later transferred to the US military jail at Guantanamo Bay where he is being held without trial.