Scott King also devoted much of her time to developing the Atlanta-based Martin Luther King Jr. Center for Nonviolent Social Change as a memorial to her husband's life and dreams. Scott King served as the center's leader until 1995, when she turned over the helm to her son Dexter.
She also led the campaign to make King's birthday, Jan. 15, a national holiday in the United States. By an Act of Congress, the first national observance of the holiday took place in 1986.
Scott King focused much of her energy during the last decade of her life on AIDS awareness and curbing gun violence.
President Bush expressed sadness and sent his condolences to the King family.
"Mrs. King was a remarkable and courageous woman, and a great civil rights leader," Bush said in a statement. "Mrs. King's lasting contributions to freedom and equality have made America a better and more compassionate nation."