After his separation from the World Wrestling Federation, Sid was hired by Extreme Championship Wrestling (1999), after back to the company WCW, where were his former colleagues of the WWF superstars fight Hulk Hogan, Randy Savage, Kevin Nash, Scott Hall, Bret Hart, and plus the new WCW superstars as Bill Goldberg, Chris Benoit. His best moment was when Sid winner WCW championship by defeating Kevin Nash twice.