Dual diagnosis of comorbid substance abuse and mental disorder is currently presenting great difficulties across Australia's health and community service sectors. Historically, mental health professionals have received relatively little formal education or training in substance abuse issues. A new curriculum on dual diagnosis was developed and tested. First, the literature was reviewed to identify barriers to curriculum change and strategies for engaging clinical staff at mental health and drug treatment services. Next, the curriculum development processes at a mental health service and neighboring drug treatment service were studied to learn how staff knowledge about dual diagnosis could be improved. A training development group and comparison group were formed to evaluate the training curriculum development process. The training development group met monthly and attended presentations of the evolving curriculum in an interactive format. Preintervention and postintervention questionnaires were distributed to both groups. Of the 187 questionnaires distributed for the first sample, 87 (47%) were returned. A comparison of training development group members' mean scores before and after the intervention revealed significant improvements in scores on the mental illness section of the questionnaire and the overall score and small but significant improvements in the substance and dual diagnosis sections. (Contains 39 references.) (MN)