The Pentagon says it has no timeline for the lifting of the ban on out gay soldiers in the US military.
The Senate voted on Saturday to repeal the law but change is expected to take months.
President Obama is expected to sign the measure into law tomorrow but this does not mean out gay troops will automatically be permitted to serve.
Instead, a 60-day process will begin after the president, Defense Secretary Robert Gates and the chairman of the Joint Chiefs of Staff, Admiral Michael Mullen, agree that the ban can be lifted.
However, it is not clear how long it will take to get to this stage.
The Pentagon has emphasised that the ban will remain in place until after the 60 days passes – meaning that gay soldiers should not come out.
Gay rights groups have asked for a moratorium on firings but this will not be implemented.
Pentagon officials must consider other aspects of repealing the law, such as whether gay troops’ partners will be treated in the same way as heterosexual servicemembers’ partners.
Another consideration is what will happen if a straight soldier refuses to share sleeping or washing quarters with one who is gay.
An estimated 14,000 troops have been fired under the 1993 law.
Speaking at the weekend, President Obama said: “It is time to close this chapter in our history. It is time to recognise that sacrifice, valour and integrity are no more defined by sexual orientation than they are by race or gender, religion or creed.
“It is time to allow gay and lesbian Americans to serve their country openly.”
The Senate passed the motion on Saturday 65-31.