The aim of the study was to identify outpatient antibiotic consumption between Jan 2000 and Dec 2005 through analysis of the HSE-Primary Care Reimbursement Services (PCRS) database as part of the Surveillance of Antimicrobial Resistance in Ireland (SARI) project. Total antibiotic consumption on the PCRS scheme between January 2000 and December 2005 expressed in Defined Daily Dose per 1000 PCRS inhabitants per day increased by 26%. The penicillin group represents the highest consumption accounting for approximately 50% of the total outpatient antibiotic use. Total DIDs for this group increased by 25% between 2000 and 2005. Co-amoxiclav and amoxicillin account for 80% of the total consumption of this group of anti-infectives. With the exception of aminoglycosides and sulfonamides which demonstrated a decrease in DID consumption of 47% and 8% respectively, all other groups of anti-infectives had an increase in DID consumption of greater than 25% during the study period. Antibiotic prescribing data is a valuable tool for assessing public health strategies aiming to optimise antibiotic prescribing.