The 71-year-old suffered from a rare form of leukaemia for several years but had kept her illiness private.
Ephron received three original screenplay Oscar nominations for her films Silkwood, When Harry Met Sally and Sleepless in Seattle and her scripts helped to define the romantic comedy genre with her trademark sharp dialogue and strong female characters.
Ephron's most recent screenwriting/directing credit was 2009's Julie and Julia, starring Meryl Streep and Amy Adams.
FROM THE ARCHIVE: The Movie Show (1989) reviews When Harry Met Sally:
FROM THE ARCHIVE: The Movie Show (1993) reviews Sleepless in Seattle: