Eunice Kennedy Shriver, founder the Special Olympics and a member of one of the most prominent American political families of the 20th century, died on Tuesday at the age of 88.
Her family said in a statement that Mrs Shriver died after she was hospitalised in Hyannis, the Massachusetts town on Cape Cod synonymous with the Kennedy family.
"Her work transformed the lives of hundreds of millions of people across the globe and they in turn are her living legacy," the family said referring to her work with the disabled.
She is survived by her husband Sargent Shriver.
Mrs Shriver was the middle child of nine born to Joseph P. and Rose Kennedy.
Her siblings include John F. Kennedy, who was elected president in 1960 and assassinated in 1963, Robert Kennedy, a New York senator whose presidential bid ended when he was assassinated in 1968, and Senator Edward Kennedy, who is battling brain cancer diagnosed in May 2008.
Mrs Shriver's children include Maria Shriver, a former television journalist who is married to California Governor Arnold Schwarzenegger.
Mrs Shriver started the Special Olympics Games in 1968 to foster fitness and self-esteem for those with mental retardation and advocated in Washington for her cause well into her eighties. The event has grown to include 190 nations.
Her concern for the mentally handicapped was attributed to her relationship with older sister Rosemary Kennedy, who was said to have been mildly retarded and spent the majority of her life in a long-term care facility after a lobotomy.
