"I am confident that we have more than 60 votes prepared to take up the defense authorization bill with the 'don't ask, don't tell' repeal if only there is a guarantee of a fair and open amendment process," Lieberman said in a report in The Hill.
Even though he is an Independent, Lieberman, a former Democrat and vice presidential candidate, caucuses with Democrats.
"Don't ask, don't tell" is the common term for a policy restricting the military from attempting to discover or reveal gay service members or applicants while blocking openly gay people from military service.
Lieberman said he hopes to avoid a lengthy debate with Republicans over the issue, which is tucked into the massive defense authorization bill.
Republican Sen. John McCain, R-Ariz., has threatened a filibuster.
"All I want is a study that assesses the impact on battle effectiveness and morale," McCain said.
Even so, Lieberman, who is a close friend of McCain's, remained positive, The Hill said.
"I repeat, there's more than 60 senators, I'm convinced, who are prepared to vote for this bill including 'don't ask, don't tell," Lieberman said.
Armed Services Committee Chairman Carl Levin, D-Mich., plans to hold hearings on the report early next month.
Levin said "I hope so" when asked if he thinks there are at least 60 votes.