Article published on the 2008-12-19 Latest update 2008-12-19 13:16 TU
Guantanamo holds prisoners the US deems to be "enemy combatants", and has been the subject of controversy since prisoners taken in Afghanistan were first brought there in 2001.
There has been much criticism of the conditions prisoners are kept in, human rights abuses and the severe interrogation techniques employed.
Closing the facility was one Obama's most-publicised campaign promises.
US Defence Secretary Robert Gates wants to be ready if Obama decides the controversial facility should be closed soon after he takes office.
"He has asked his team for a proposal on how to shut it down," said a spokesperson from the Pentagon.
Nearly 800 detainees have done time in Guantanamo, and it has grown into a state-of-the-art maximum security complex with a number of separate detention centres including Camp Delta and Camp Iguana.
Around 400 prisoners have been released without charge.
Gates wants to make sure he is ready to fulfil Obama's promise as there are a number of difficulties in dealing with the remaining 250 inmates.
Some foreign prisoners will be returned to their countries, although the US has had problems in convincing some states that prisoners are no longer a threat.
And there is the issue of military trials for suspects. Obama has suggested he would put an end to military tribunals, but the Pentagon has gone ahead with them.
There are also worries that if suspects are released from Guantanamo that they should be denied the right to automatic asylum in the US.