With 10 days left in office, Defense Secretary Donald H. Rumsfeld bade a sometimes emotional farewell to Pentagon employees Friday, saying the single worst day of his nearly six years in office was the day in spring 2004 when he learned of the prisoner abuse that took place at Abu Ghraib.

In a question-and-answer session, he was asked what were his best day and his worst day.

"Clearly, the worst day was Abu Ghraib, seeing what went on there and feeling so deeply sorry that that happened," he said without hesitation, referring to the scandal that triggered worldwide condemnation and prompted him to twice offer his resignation to President Bush in 2004. Bush rejected those offers.

"I guess my best day, I don't know, may be a week from Monday," he said with a big grin, referring to the fact that his successor, Robert Gates, is scheduled to take over at the Pentagon on Dec. 18.

In prepared remarks to his audience, Rumsfeld predicted that the period since he took office in January 2001 would eventually be seen as one of "enormous challenge and historic consequence."

Asked how he wants history to remember him, he said simply, "Better than the local press."

With a couple of dozen troops from each military service and a few civilian Pentagon employees seated behind him on stage in the Pentagon's main auditorium, Rumsfeld spoke to an audience of several hundred people. With a big smile, he strode into the room to a cascade of applause and a few approving yelps.

"I suspect this will be among my last public remarks as secretary of defense," he said. His last full day will be Dec. 17.

It was one of the few public appearances Rumsfeld has made since Bush announced on Nov. 8 at the White House that he was replacing Rumsfeld with Gates to get a "fresh perspective" on the Iraq war. Gates won confirmation by the Senate this week.

Rumsfeld applauded the work and dedication of Pentagon employees and said he was proud to have been associated with them.

"Each of you and future generations of Americans, as well as future generations of Iraqis and Afghans, will be able to look on these past years as a time of enormous challenge and historic consequence," he said.

"As I leave at the end of my second — and, good Lord willing, my last — (term) I do leave believing as I did 30 years ago that America is a truly great nation, that the American people are wise and decent," he said.

He was introduced on the stage by Gen. Peter Pace, the chairman of the Joint Chiefs of Staff, who lauded Rumsfeld as a man of courage, integrity and vision.

"This man's work ethic is incredible," Pace said. "Is he demanding? You bet." Rumsfeld then interrupted, saying with a laugh, "No! I've been on my best behavior."

Rumsfeld, 74, is one of the longest-serving defense secretaries in U.S. history and is the only person to have held the position twice. His first stint was from November 1975 to January 1977, when he held the distinction of being the youngest defense secretary in history.