In 2009, some 428 members of the military, 259 men and 159 women, were discharged for violating the rules on homosexual activity, the lowest number of discharges in 30 years, according to recently released Department of Defense statistics.
Discharges under "don't ask, don't tell" peaked in 2001, when 1,227 service members were separated from the military.
The two senior defense officials' visit to Congress comes on the heels of President Obama State of the Union address last week in which he pledged to "work with Congress" to repeal the ban.
His announcement, supporters say, makes good on a campaign promise some of his most ardent backers felt he ignored during his first year in office.
"This year, I will work with Congress and our military to finally repeal the law that denies gay Americans the right to serve the country they love because of who they are. It's the right thing to do," he said during his speech Jan. 27.
Gay-rights groups were quick to applaud the plan to review the policy with an eye towards its repeal.
"Today is a historic step forward in repealing a shameful law that has harmed the military, discharged thousands of talented and patriotic Americans and prevented thousands more from serving their country," said Human Rights Campaign in a statement following the hearing.