A by-election was held for the Legislative Assembly of Queensland district of Chatsworth on 20 August 2005. It was triggered by the resignation of sitting Labor member and Deputy Premier Terry Mackenroth.
The by-election was held to coincide with the Redcliffe by-election on the same day. Both contests resulted in the Labor Party losing the seat to the rival Liberal Party. Michael Caltabiano was elected as the new member for Chatsworth.