Her book publisher Alfred A. Knopf confirmed her death in a statement.
Born into a family of screenwriters, Ephron was a top journalist in her 20s and 30s, then a bestselling author and successful director. She was among the most quotable and influential writers of her generation. She wrote and directed such favourites as Julie & Julia and Sleepless in Seattle.
Heartburn, starring Meryl Streep and Jack Nicholson, chronicled her own dissolving marriage with journalist Carl Bernstein and was based on her novel of the same name.
Ephron was married three times: to Dan Greenburg, Bernstein and Nicholas Pileggi, who survives her. She had two sons, Jacob and Max Bernstein.