The beaded gown was a star attraction at 10 inaugural balls held in January 2009 to celebrate President Barack Obama's swearing-in. It was designed by Jason Wu of New York.
The Smithsonian Institution says all first ladies since 1912 have contributed to the collection, though not all have parted with their ball gowns.
Mrs. Obama's gown will join those currently on display from Helen Taft, Eleanor Roosevelt, Rosalynn Carter and Laura Bush.
