This report investigates the prevalence of mental illness in association with common chronic diseases and shows that in 2007: 12% of Australians aged 16-85 had a mental disorder and a physical condition at the same time; the most common comorbidity was anxiety disorder combined with a physical condition, affecting around 1.4 million (9%) Australian adults; people living in the most disadvantaged areas of Australia were 65% more likely to have comorbidity than those living in the least disadvantaged areas.