<Tr> <Td_colspan="2"> ← Previous Season 11 Next → Season 13 </Td> </Tr> <Tr> <Td_colspan="2"> List of Grey's Anatomy episodes </Td> </Tr> <P> The twelfth season of the American television medical drama Grey's Anatomy was ordered on May 7, 2015, by ABC . It premiered on September 24, 2015, in the United States on ABC . The twelfth season includes the show's 250th episode, Guess Who's Coming to Dinner, which is the fifth episode in the season . The season is produced by ABC Studios, in association with Shondaland Production Company and The Mark Gordon Company; the showrunner being Shonda Rhimes . The season commenced airing with the episode "Sledgehammer" and concluded with "Family Affair". </P> <P> This season was the first not to feature Patrick Dempsey as Dr. Derek Shepherd following the death of the character at the end of the eleventh season . On June 5, 2015 ABC announced that Jason George has been promoted to series regular status after having performed a recurring role as Dr. Ben Warren since the sixth season of the medical drama . Part way into the season Martin Henderson was introduced as new regular character, Dr. Nathan Riggs . In the tenth episode of the season Giacomo Gianniotti was also promoted to series regular status as intern Andrew DeLuca . </P>

When did season 12 of grey's anatomy start