The cause of death was pneumonia brought on by acute myeloid leukemia, her son Jacob Bernstein told The New York Times.
Ephron was nominated for three screenwriting Oscars, for "Silkwood" (with Alice Arlen), "When Harry Met Sally ... " and "Sleepless in Seattle" (with David S. Ward and Jeff Arch). Her screenwriting credits also include
"Julie and Julia," "Hanging Up," "Michael," "My Blue Heaven" and "Heartburn" -- based on her novel of the same name marriage to Washington Post reporter Carl Bernstein.
Her directing credits include "Julie & Julia," "You've Got Mail" and "Sleepless in Seattle."
Born in New York May 19, 1941, Ephron was the daughter of screenwriters Henry Ephron and Phoebe Ephron, who collaborated on "Desk Set," "Carousel" and "Daddy Long Legs."
Besides Jacob and Carl Bernstein, Ephron is survived by another son she had with Bernstein, Max; her third husband, "Goodfellas" writer Nicholas Pileggi; and her sisters Delia Ephron and Amy Ephron, People.com said.
'Maze Runner' brings in $11.3M Friday
Dakota Fanning says her mother is no stage mom