The 2005 Australian Formula 4000 Championship was a CAMS sanctioned motor racing title for drivers of Formula 4000 racing cars. This was the first title to be contested under the Australian Formula 4000 Championship name although the category had competed for the Australian Drivers' Championship under its previous Formula Holden and Formula Brabham names from 1989 to 2002 and then as Formula 4000 in 2003 and 2004.