Adm. Mike Mullen, Joint Chiefs of Staff chairman, said Wednesday about 400,000 military personnel and members of 150,000 families were surveyed, CQ Politics reported.
Mullen advocates repeal of the "don't ask, don't tell" law but has cautioned Congress to wait for the Pentagon to "crunch the data" from its survey before it considers ending the policy.
The Pentagon has enough data to be statistically significant, Mullen said.
"The reason to conduct the survey is to get objective data from the people affected most by this change," Mullen said. "It is that data that will highlight issues in terms of implementation and issues that need to be addressed before certification."
He said issues affecting force readiness, training and cohesion would be specifically examined.
"These are real things we have to deal with," Mullen said, adding that the troops' input was important because, in part, "this force has been stretched."
Final results are due to Defense Secretary Robert Gates by Dec. 1.
The Senate last week blocked consideration of the defense authorization bill, in part because of GOP objections over the repeal of "don't ask, don't tell" and other measures Democrats wanted included in the bill.