Objectives There is a lack of evidence to guide the management of cellulitis in the emergency department (ED). The primary aim of this study was to characterize antibiotic-prescribing practices for the treatment of cellulitis in Irish EDs. Secondary aims were to identify patient variables associated with the prescription of intravenous (i.v.) antibiotics and to describe the utility of three published guidelines for the management of cellulitis in the ED.Methods This was a multicentre, prospective, observational cross-sectional study of consecutive patients presenting to six EDs in Ireland over a 1-month period (June 2012).Results In total, 117 patients were enrolled. Fifty-five percent of all patients (n=65) were referred from primary care, and emergency physicians prescribed i.v. therapy in 50% of patients (n=59) overall. Nonpurulent cellulitis accounted for 96.5% of cases (n=113). Flucloxacillin, either alone or with penicillin V, is the most commonly prescribed oral antibiotic in patients both referred from primary care and discharged from the ED. Flucloxacillin with benzylpenicillin is the most commonly prescribed i.v. treatment. Fever, increasing diameter of infection, and tinea pedis were associated with prescription of i.v. antibiotics by emergency physicians. The three guidelines examined in this study recommended oral antibiotic treatment for between 33-44% of patients who were treated with i.v. antibiotics by emergency physicians.Conclusion In Ireland, current prescribing practices for CREST 1 and modified CREST 1 and 2 patients are poorly adherent to guideline recommendations. Copyright (C) 2016 Wolters Kluwer Health, Inc. All rights reserved.