Background: Alcohol-related hospital attendances at Emergency Departments (ED) are a potentially avoidable burden on National Health Services (NHS) resources. Understanding the number and type of patients attending EDs with alcohol intoxication is important in estimating the workload and cost implications. We used best practice from previous studies to establish the prevalence of adult alcohol-related ED attendances and estimate the costs of clinical management and subsequent health service use. Methods: The setting was a large inner-city ED in northeast England, United Kingdom. Data were collected via (i) retrospective review of hospital records for all ED attendances for four pre-specified weeks in 2010/11 to identify alcohol-related cases along with 12 months follow-up of the care episode, and (ii) prospective 24/7 assessment via breath alcohol concentration testing of patients presenting to ED in the corresponding weeks in 2012/13. Results: The prevalence rates of alcohol-related attendances were 12% and 15% for the retrospective and prospective cohorts. Prospectively, the rates ranged widely from 4% to 60% during the week, rising to over 70% at weekends. Younger males attending in the early morning hours at weekends made up the largest proportion of alcohol-related attendances. The mean cost per attendance was £249 (SD £1,064); the mean total cost for those admitted was £851 (SD £2,549). The most common reasons for attending were trauma-related injuries, followed by psychiatric problems. Conclusions: Alcohol-related attendances are a major and avoidable burden on emergency care. However, targeted interventions at weekends and early morning hours could capture the majority of cases and help prevent future re-attendance.