Emergency medicine plays a central role in the early recognition of patients presenting to hospital with sepsis. However, the epidemiology of sepsis in the Irish Emergency Department (ED) setting has not been described. The primary aim of this study was to determine the proportion of adult ED patients who meet the current criteria for uncomplicated sepsis. This cross-sectional study was performed in the ED of Beaumont Hospital, Dublin. The clinical records of all patients presenting to the ED over a four-week period were retrospectively screened to determine if they met the current Health Service Executive (HSE) criteria for uncomplicated sepsis. Overall, 3,585 adult patients attended the ED during the study period, with 152 patients meeting the criteria for uncomplicated sepsis. The proportion of ED patients who met the criteria for uncomplicated sepsis was 4.24% (95% CI 3.57-4.91%).