BACKGROUND AND OBJECTIVE:Bronchiectasis not associated with cystic fibrosis is an increasingly recognized chronic lung disease. In Oceania, indigenous populations experience a disproportionately high burden of disease. We aimed to describe the natural history of bronchiectasis and identify risk factors associated with premature mortality within a cohort of Aboriginal Australians, New Zealand Māori and Pacific Islanders, and non-indigenous Australians and New Zealanders. METHODS:This was a retrospective cohort study of bronchiectasis patients aged >15 years at three hospitals: Alice Springs Hospital and Monash Medical Centre in Australia, and Middlemore Hospital in New Zealand. Data included demographics, ethnicity, sputum microbiology, radiology, spirometry, hospitalization and survival over 5 years of follow-up. RESULTS:Aboriginal Australians were significantly younger and died at a significantly younger age than other groups. Age- and sex-adjusted all-cause mortality was higher for Aboriginal Australians (hazard ratio (HR): 3.9), and respiratory-related mortality was higher for both Aboriginal Australians (HR: 4.3) and Māori and Pacific Islander people (HR: 1.7). Hospitalization was common: Aboriginal Australians had 2.9 admissions/person-year and 16.9 days in hospital/person-year. Despite Aboriginal Australians having poorer prognosis, calculation of the FACED score suggested milder disease in this group. Sputum microbiology varied with Aspergillus fumigatus more often isolated from non-indigenous patients. Airflow obstruction was common (66.9%) but not invariable. CONCLUSIONS:Bronchiectasis is not one disease. It has a significant impact on healthcare utilization and survival. Differences between populations are likely to relate to differing aetiologies and understanding the drivers of bronchiectasis in disadvantaged populations will be key.