The pitch, which started in February, originally involved Publicis Mojo, Singleton Ogilvy & Mather, Whybin\TBWA and incumbent agency M&C Saatchi.
M&C Saatchi was behind the controversial "Where the bloody hell are you?" campaign, which ran into trouble and racked up hundreds of complaints. DDB and Saatchis presented final pitches in Sydney at the end of May.
DDB will work with Tourism Australia to maximise the marketing opportunities ahead of the Baz Luhrmann movie 'Australia', which is scheduled for release in the UK in November.
Marty O'Halloran, CEO and chairman DDB Australia and New Zealand, said: "This is a tremendous win for DDB and we are really looking forward to working closely with the Tourism Australia team to build an energetic and dynamic brand.
"The response to Tourism Australia was an integrated approach that reflected the creativity, connectivity and collaboration of the DDB Global Network."
Tourism Australia is currently finalising its media selection with a decision expected shortly.
Rick Allert, Tourism Australia chairman, said: "In appointing DDB Worldwide, we have chosen an agency partner that not only provides the requisite international network and infrastructure credentials, but is also, most importantly, at the top of the creative game globally."