Chambliss's press office issued a statement saying it was unclear who was responsible for the online post and the matter has been referred to the Senate sergeant at arms, The Atlanta Journal-Constitution reported.
"The (sergeant at arms) has worked side by side with our personnel to determine whether the comment in question emanated from our office," the statement said. "That appears to be the case."
The homophobic comment was posted as part of an Internet discussion on the debate over the U.S. military's "don't ask, don't tell" policy forbidding gays and lesbians from serving openly in the armed forces. A commenter who identified himself only as "Jimmy" posted a message on the Joe.My.God blog saying "All faggots must die."
Joseph Jervis of New York, the author of the blog, said a search using the Internet Protocol address associated with the post traced its origin to the neighborhood of Chambliss's office in Atlanta, the Journal-Constitution reported.
"This office has not and will not tolerate any activity of the sort alleged," Chambliss spokeswoman Bronwyn Lance Chester told the newspaper.
The offending comment was posted shortly after U.S. Senate Republicans filibustered to prevent debate on a defense appropriations bill containing language that would repeal the "don't ask, don't tell" policy.
Ohio bar shooting arrested, charged with murder
Duggar sisters unveil Christian dating rules in new book