She was 48 when she was found unconscious in her mansion in Newport, R.I., in 1980 and 76 when she died.
A spokeswoman for von Bulow's family released a statement confirming her death, The New York Times reported. Her children said she was "an extraordinary loving and caring mother."
Claus von Bulow, her second husband, was charged with giving her an overdose of insulin. He was convicted, won on appeal and then acquitted in a series of highly publicized trials.
A civil suit by von Bulow's two children from her first marriage was settled with Claus agreeing to a divorce. He now lives in London.
Von Bulow is survived by her three children, Annie-Laurie von Auersperg Kneissl Isham and Alexander von Auersperg from her first marriage, Cosima Pavoncelli from her second, and five grandchildren.