Problems associated with alcohol and other drug (AOD) use cost Australia over $25 billion per year. In response to concerns about AOD use, federal and state governments have devised a range of policies and public health measures aimed at prevention, education and treatment. All three areas are highly complex, shaped by social and political forces and struggles. Using an international comparative method involving Australia and Canada, this research will analyse the key concept underlying much of the political struggle over AOD policy and service provision: addiction. This analysis will better inform policy, and help develop clearer models and more productive approaches for improving AOD-related health and social outcomes in Australia.