John Thoresen, director of the Barbara Sinatra Children's Center, said she died of natural causes at her home in Rancho Mirage, California, surrounded by family and friends.
The former model and Las Vegas showgirl was a committed, high-profile advocate for abused children. In 1986, she and her late husband, Frank set up the Barbara Sinatra Children's Center in Rancho Mirage, near Palm Springs. The non-profit facility provides therapy for children who have been physically, sexually and emotionally abused.
Mrs Sinatra is survived by her son, Robert Oliver Marx, his wife Hillary, and her granddaughter, Carina Blakeley Marx.