Supernatural (U.S. TV series) was first aired on The WB.
Supernatural (U.S. TV series) . It was first broadcast on September 13 , 2005 , on The WB , and subsequently became part of successor The CW 's lineup . The pilot was viewed by an estimated 5.69 million viewers , and the ratings of the first four episodes prompted The WB to pick up the series for a full season .