Background: Individuals who self-harm frequently misuse alcohol and have increased risk of subsequent death. We aimed to assess alcohol-related premature death in people who self-harm compared to the general population, including variation by socio-economic deprivations. Design: A retrospective longitudinal cohort analysis from the Multicentre Study of Self-harm in England, 1st January 2000 to 31st December 2010, with cause-specific mortality follow-up through to 31st December 2012. Participants: All individuals aged 15 years or more who presented with self-harm (n=39014) to general hospital emergency departments , together with follow-up mortality information from the Data Linkage Service of the Health and Social Care Information Centre. Setting: Six emergency departments in the cities of Oxford, Manchester and Derby. Main outcome measures: Standardised mortality ratios (observed/expected number of deaths: SMR) and mean number of years of life lost (YLL) were estimated for alcohol-related mortality. Patients’ characteristics and clinical management following self-harm were also examined. Results: After 7.5 years (median) follow-up, 2695 individuals (6.9%) had died, significantly more males (9.5%) than females (5.0%), including 307 (11.4%) from alcohol-related causes. Alcohol-related death was more frequent than expected in both males [SMR 8.5, 95% CI 7.3 to 9.8] and females [11.6, 9.8 to 13.7], equating to 33.7 YLL [95% CI 32.4 to 35.0] in males and 38.1 YLL [36.6 to 39.6] in females. It was not associated with area-level socio-economic deprivation. Alcohol-related death was associated with unemployed/ sick/disabled status, alcohol use during self-harm, referral to drug/alcohol services, and lack of psychosocial assessment following self-harm. Conclusions: Hospital-presenting self-harm patients should receive assessment following self-harm according to national guidance to enable early identification and treatment of alcohol problems.