It was renewed for its 15th season back in January this year, along with 10 other CW shows including Charmed and Riverdale.
Padalecki, Ackles and Misha Collins posted an Instagram video that revealed the 15th season would be their last.
A number of other CW series have recently been announced to end with a final season, including Crazy Ex-Girlfriend, which will end in April, and Jane the Virgin, which will end after its fifth season that begins on 27 March.
The stars of popular TV series Supernatural have announced that the show will end after 15 seasons.