OBJECTIVES:  To describe the utilisation of and expenditure on antibiotics on the general medical services (GMS) scheme in Ireland from 2012 to 2015. METHODS: Retrospective cross-sectional studies of antibiotic utilisation conducted using the national pharmacy claims database for the means tested GMS scheme from January 2012 to December 2015. The scheme over-represents elderly, female and younger aged population. Antimicrobial utilisation was reviewed as defined daily doses (DDDs) per 1000 eligible population per day (TID) and total ingredient costs. ATC code J01 was used and included all ages (<16, 16-44, 45-64 and 65+ years). Log-linear regression was used to examine changes over time. RESULTS: Total antibiotic items dispensed fell from 2,874,228 to 2,629,379 from 2012 to 2015 which was a reduction in the rate of items/1000 population from 1550 to 1487. The total costs fell from €17.93million in 2012 to €16.19million in 2015. Total DDDs/TID overall showed a slight increase from 34.03 to 35.39 (p<0.001). However, this increase was most prominent in the older age category (65+ years) where DDD/TID significantly increased from 50.20 to 56.94 between 2012 and 2015 (p<0.001), compared to younger aged populations (<16 years) which decreased from 20.99 to 20.75 DDD/TID between 2012 and 2015 (p<0.001). Combinations of penicillins and beta-lactamase inhibitors were the most commonly prescribed antibiotic over the period analysed (8.26 DDD/TID in 2012 to 8.57 DDD/TID in 2015). Utilisation of extended spectrum penicillins increased slightly from 4.81 DDD/TID in 2012 to 5.07 in 2015 (p<0.001). CONCLUSIONS: While the rate of prescribing items for antibiotics reduced over the 4 years of study there has been a slight year on year increase in the use of antibiotics when analysed as DDD/TID. Future initiatives should focus on antibiotic prescribing in the older population (65+ years) and on the over-use of combination penicillin and beta-lactamase inhibitors to reduce inappropriate antibiotic prescribing.