Objective: To quantify the direct cost of alcohol-related presentations to Royal Perth Hospital ED, as part of the binational Alcohol Harm in Emergency Departments study. Methods: Secondary analysis of a prospective observational study of all ED presentations over a 168-h period in December 2014. Direct costs for health service usage were based on activity-based costing methodologies from the Royal Perth Hospital Business Intelligence Unit. Patients were classified as either alcohol positive or alcohol negative (using predetermined criteria) to determine the direct cost of these presentations. Results: Of the 213 alcohol-positive presentations in the original study, 206 had costing data available. Direct cost of care in the ED for alcohol-positive patients was $121 619 across all age groups during the study week (annual estimate $6.3 million). This cost was largely driven by injuries. On average, the direct cost of care in the ED was $590 per alcohol-positive and $575 per alcohol-negative patient. Costs of care provided in the ED were largely attributable to ED (72%) and radiology (17%) services. Extrapolation using mean costs for the patients without costing data, the study week cost was $144 629, with the annual estimate $7.5 million. Conclusions: Alcohol-related presentations to the ED are a significant public health burden. If the study week is representative, the annual cost is substantial. Although the direct mean cost of presentations to the ED is similar between alcohol-positive and alcohol-negative patients, these presentations would not have occurred without the influence of alcohol.