<Tr> <Th_colspan="2"> External links </Th> </Tr> <Tr> <Td_colspan="2"> Official website </Td> </Tr> <P> Grey's Anatomy is an American medical drama television series that premiered on March 27, 2005, on American Broadcasting Company (ABC) as a mid-season replacement . The fictional series focuses on the lives of surgical interns, residents, and attending physicians, as they develop into seasoned doctors while trying to maintain personal lives and relationships . The title is a play on Gray's Anatomy, a classic human anatomy textbook first published in 1858 in London and written by Henry Gray . Shonda Rhimes developed the pilot and continues to write for the series; she is also one of the executive producers, along with Betsy Beers, Mark Gordon, Krista Vernoff, Rob Corn, Mark Wilding, and Allan Heinberg . Although the series is set in Seattle (at the fictional Seattle Grace, later known as the Grey - Sloan Memorial Hospital), it is filmed primarily in Los Angeles, California . The show was originally titled Complications, a double - edged reference to both the complicated medical procedures and personal lives of the characters . </P> <P> The series was designed to be racially diverse and used color - blind casting . It revolves around the title character, Dr. Meredith Grey, played by Ellen Pompeo, first featured as an intern . The original cast consisted of nine star - billed actors: Pompeo, Sandra Oh, Katherine Heigl, Justin Chambers, T.R. Knight, Chandra Wilson, James Pickens Jr., Isaiah Washington and Patrick Dempsey . The cast has undergone major changes through the series' run, with many members leaving and being replaced by others . In its twelfth season, the show had a large ensemble of sixteen actors, including four characters from the original cast (Meredith Grey, Alex Karev, Miranda Bailey, and Richard Webber). </P>

When did the first episode of greys anatomy air