A military Honor Guard moved five flag draped caskets from the National Memorial Cemetery of the Pacific in Hawaii on Monday.
"This is called a Dignified Transfer. It's very personal to those of us who work here at Punchbowl," cemetery public affairs specialist Gene Maestas told Honolulu CBS affiliate KHNL.
The caskets contained the remains of some of the 388 sailors and Marines who were aboard the USS Oklahoma when Japan attacked Pearl Harbor on December 7, 1941. The remains have been buried in 45 graves marked "unknown."
Relatives of 85 percent of the battleship's crew supplied DNA and family records to aid the identification of the remains.
"It'll take some time obviously. Co-mingled remains of so many in 61 caskets will take some time. I think we have a very strong probability of identifying certainly the majority of them," said Michael Linnington, director of the Defense POW/MIA Accounting Agency.
Initial work will be done in the POW/MIA Accounting lab in Hawaii, much of it in a new $85 million facility on Joint Base Pearl Harbor - Hickam. The remains will then be sent to the lab in Omaha, Nebraska, for more detailed study.
"Three hundred and eighty-eight heroes from the USS Oklahoma in total will be disinterred by the end of this summer," Linnington said.
The agency estimates it will take five years to finish the identification work. Families across the United States have waited more than 70 years for this day to arrive.