Publicist Edward Lozzi announced her death.
"We were on the phone minutes before she died. We were discussing her book she was writing and a possible deal. She had to go to the restroom. She never made it out," he said.
Born Constance Francesca Gabor Hilton, Hilton worked in several fields including photography and acting. She once took a summer job at the Beverly Hills Hilton taking reservations, where guests expressed incredulity when she informed them of her name.
Hilton has long been in the center of major money battles. When her father died in 1979, Hilton was left $100,000 while most of his multimillion dollar fortune was left to his foundation. Hilton fought for a larger inheritance in court but lost.
She has also been fighting with her mother's husband Frederik von Anhalt over control of her mother's finances and healthcare.
Gabor is 97 and requires 24/7 care due to a series of health crises including a broken hip, blood clots and a leg amputation.
At one point, a judge ahad to order von Anhalt to allow Hilton to see her mother.
Hilton was pronounced dead at Cedars-Sinai Hospital in Los Angeles.