Accompanied by Defence Secretary Leon Panetta and Admiral Mike Mullen, the joint chiefs of staff chairman, Obama signed the notice and sent it to the Congress certifying that military preparedness would not be affected by revoking the "don't ask, don't tell" policy.
In a statement, the US President said, "As commander in chief, I have always been confident that our dedicated men and women in uniform would transition to a new policy in an orderly manner that preserves unit cohesion, recruitment, retention and military effectiveness."
He added, "Today's action follows extensive training of our military personnel and certification by Secretary Panetta and Admiral Mullen that our military is ready for repeal. As of September 20th, service members will no longer be forced to hide who they are in order to serve our country."
The move got applauds from human right and gay right activists.
Joe Solmonese, Human Rights Campaign President said, "The president's certification of repeal is a monumental step, not just for those forced to lie in order to serve, but for all Americans who believe in fairness and equality."
However, the decision has also got its share of brickbats, especially from former US military personnel, who believe that such a move could affect the cohesion between soldiers.
The Pentagon is now expected to prepare the American troops for the change, and finalise legal and technical details, including how it will affect housing, military transfers and other health and social benefits.
The ban that was imposed in 1996 will now be lifted within 60 days.