Abstract: Objective To identify important causes of premature mortality among Aboriginal adults in the Northern Territory (NT), 1979-1991. Methods All deaths of NT Aboriginal residents aged 15-64 years which occurred in the NT between 1979 and 1991 and which were recorded by the Registry of Births, Deaths and Marriages were included. Standardised mortality ratios (SMRs) were used to compare the number of deaths observed among Aboriginals in the NT to those expected, based on overall Australian rates. Years of potential life lost before age 65 (YPLL.as) were estimated for specific causes of death. Results Aboriginal women (overall SMR, 5.5) and Aboriginal men (SMR, 4.7) experienced a high burden of excess mortality from almost every cause of death. This excess increased over time, especially for Aboriginal women. Among Aboriginal men, the most important causes of premature death were motor vehicle accidents (11% of excess deaths and 17% of YPLL.as), ischaemic heart disease (10% of excess deaths and 10% of YPL4s), pneumonia and influenza (8% of excess deaths and 6% of YPLL65), and homicide (7% of excess deaths and 8% of YPL4s). For Aboriginal women, the most important causes included homicide (7% of excess deaths and 11%of YPLL65), chronic obstructive pulmonary disease (10% of excess deaths and 5% of YPLL65), rheumatic heart disease (7% of excess deaths and 8% of YPLL.as), and ischaemic heart disease (6% of excess deaths and 5% of YPLLe5). Conclusions The wide variety of causes of excess mortality will require an equally wide variety of solutions, both medical and non-medical, and a long term commitment will be necessary to achieve reductions in premature mortality among NT Aboriginal adults.