AbstractBackground and AimsAlcohol consumption is a leading risk factor for premature mortality globally, but there are limited studies of broader cohorts of people presenting with alcohol‐related problems outside of alcohol treatment services. We used linked health administrative data to estimate all‐cause and cause‐specific mortality among individuals who had an alcohol‐related hospital inpatient or emergency department presentation.DesignObservational study using data from the Data linkage Alcohol Cohort Study (DACS), a state‐wide retrospective cohort of individuals with an alcohol‐related hospital inpatient or emergency department presentation.SettingHospital inpatient or emergency department presentation in New South Wales, Australia, between 2005 and 2014.ParticipantsParticipants comprised 188 770 individuals aged 12 and above, 66% males, median age 39 years at index presentation.MeasurementsAll‐cause mortality was estimated up to 2015 and cause‐specific mortality (by those attributable to alcohol and by specific cause of death groups) up to 2013 due to data availability. Age‐specific and age–sex‐specific crude mortality rates (CMRs) were estimated, and standardized mortality ratios (SMRs) were calculated using sex and age‐specific deaths rates from the NSW population.FindingsThere were 188 770 individuals in the cohort (1 079 249 person‐years of observation); 27 855 deaths were recorded (14.8% of the cohort), with a CMR of 25.8 [95% confidence interval (CI) = 25.5, 26.1] per 1000 person‐years and SMR of 6.2 (95% CI = 5.4, 7.2). Mortality in the cohort was consistently higher than the general population in all adult age groups and in both sexes. The greatest excess mortality was from mental and behavioural disorders due to alcohol use (SMR = 46.7, 95% CI = 41.4, 52.7), liver cirrhosis (SMR = 39.0, 95% CI = 35.5, 42.9), viral hepatitis (SMR = 29.4, 95% CI = 24.6, 35.2), pancreatic diseases (SMR = 23.8, 95% CI = 17.9, 31.5) and liver cancer (SMR = 18.3, 95% CI = 14.8, 22.5). There were distinct differences between the sexes in causes of excess mortality (all causes fully attributable to alcohol female versus male risk ratio = 2.5 (95% CI = 2.0, 3.1).ConclusionsIn New South Wales, Australia, people who came in contact with an emergency department or hospital for an alcohol‐related presentation between 2005 and 2014 were at higher risk of mortality than the general New South Wales population during the same period.