OBJECTIVES: To obtain a retrospective profile of public expenditure in antibiotics. METHODS: Data for calculating the anual rates of public expenditure in antibiotics was obtained from databases provided by the Ministry of Health and the Social Security Fund. A semilogarithmic regression was assesed to obtain the average anual growth rates. For trend analysis, we used the statistic software Joint Point Regression 4.2.0.2. RESULTS: Expenditure in antibiotics accounts for 57% of the anual global expenditure in antimicrobials. Antibiotics have experienced a decreasing trend of -0.1018 (t = -5.9116, p = 0.0010). In a separate analysis for antibiotic type we found a trend of -0.1539 (t = -3.5827, P = 0.0117) for the carbapenems group. Regarding the expenditure for benzylpenicillins a change in trends was observed since 2012: from 2007 to 2012 expenditure rose up in 0.1623 (t = 3.4449, p = 0.0411) and from 2012 to 2014 it fell in -1.2090 (t = -4.8851, p = 0.0164). The antibiotic type which expenditure experienced the most important growth were the oxazolidinones in 0.2526 (t = 6.1655, p = 0.0008). CONCLUSIONS: The observed changes in trends for the benzylpenicillins might be explained for a decrease in the clinical indications for their use. Regarding the carbapenems, restriction of their prescription due to a rise in bacterial resistance cases could be the cause for a decrease in public expenditure. Otherwise, the rising in expenditure for oxazolidinones might obey to this latter situation. A change in trends for public expenditure in antibiotics has been observed, which could be due to an increase of the investment in other antimicrobials in response to a rise in the incidence of infectious diseases as HIV.