BACKGROUND: The Rome Foundation Global Epidemiology Study on the disorders of gut-brain interaction (DGBI) was used to assess the national prevalence of all 22 DGBI, the percentage of respondents meeting diagnostic criteria for at least one DGBI, and the rates of comorbid anxiety, depression, and somatization in Australia and 25 other countries. METHODS: The survey was conducted in Australia and 25 other countries through the Internet and included the Rome IV Diagnostic Questionnaire and an in-depth supplemental questionnaire. KEY RESULTS: Two thousand thirty-six Australian adults completed the survey nationwide: mean age 47.34 ± 17.00 years, 50.15% males. Overall, 38.67% of Australians met criteria for at least one DGBI, with unspecified functional bowel disorder (8.01%) and then functional constipation (7.71%) being the most prevalent. For those Australians with at least one DGBI, rates of anxiety, depression, and somatization where high (26.58%, 28.96%, and 63.10%, respectively), with functional chest pain having the highest rates of anxiety (55.00%) and depression (57.50%), and irritable bowel syndrome (mixed) having the highest somatization rate (75.86%). The odds of having a DGBI increased with greater anxiety (OR: 1.09, CI 95%: 0.97, 1.23), depression (OR: 1.17, CI 95%: 1.04, 1.32), and somatization (OR: 1.17, CI 95%: 1.14, 1.20) symptom severity. CONCLUSIONS AND INFERENCES: The current study represents the most comprehensive epidemiological exploration of DGBI and mental health in Australia to date, including their prevalence and distributions across sex and age, associations between DGBI and anxiety, depression, and somatization. The findings warrants future comparisons between population characteristics and health care systems differences in order to reduce the burden of DGBI and mental illness worldwide.