US Defence Secretary Robert Gates has issued a new mandate that only five senior officials can expel someone from the military for being gay.
The five officials charged with decision-making are all civilians.
The procedural change comes as courts weigh the legality of the military's "don't ask, don't tell" policy, which bars openly gay people from serving.
A California judge's ruling that the 17-year-old policy is unconstitutional has been temporarily overturned.
Prior to this change, a large number of less senior officials, both civilian and military, could decide to discharge gay servicemen and women.
The new process will require the secretary of the relevant branch of service - army, navy or air force - to consult a senior Pentagon lawyer and the undersecretary of personnel before reaching a group decision.
Mr Gates's memo announcing the shift said it would be in place "until further notice".
The Pentagon is currently assessing the impact that allowing openly gay servicemen and women may have on military readiness and effectiveness, and is due to release a report on 1 December.
But in the meantime, the defence department has been ricocheted between legal rulings first first allowing, then denying, gay men and women the right to enlist.
The Obama administration has voiced support for ending "don't ask, don't tell" but argues that any repeal of the policy should be undertaken by Congress, not the courts.