Appropriate antibiotic use improves patient outcome and prevents the emergence of antibiotic resistance. A point-prevalence audit of antibiotic use at Beaumont Hospital, Dublin was carried out during the collection of data for the 2006 Hospital Infection Society (HIS) Prevalence Survey of Healthcare-Associated Infection. All inpatients who met the HIS survey entry criteria were included in the HIS survey, and all inpatients who were receiving antibiotics at the time of the survey were included in the point-prevalence audit of antibiotic use. Among these, 7.18% and 36.8% of patients had a healthcare-associated infection (HCAI) and were on antibiotics, respectively. Unnecessary collection of duplicate data was avoided by conducting an audit of antibiotic use and a national survey of HCAI simultaneously.