Resumo:Objetivo: Avaliar a utilização de medicamentos potencialmente inapropriados (MPIs) para idosos em um hospital público e identificar se existe correlação entre sua prescrição e a polifarmácia. Palavras-chave:Idosos; medicamentos potencialmente inapropriados; prescrição inadequada; farmacoepidemiologia. Abstract: Objectives:To evaluate the use of potentially inappropriate medications (PIM) for older adults in a public hospital and the correlation between its prescribing and polypharmacy. Method: Observational, cross-sectional study in a public hospital of medium and high complexity. Data collected through a form of collection structured on the electronic patient record and filed printed record. The analyzed period was June 2014 to May 2015. To evaluate the PIMs were used the Beers criteria, versions 2012 and 2015. Results: Were analyzed the prescriptions of 226 patients (60.2% male). The mean age was 71.1 years and the average inpatient days were 9.1. The prevalence of polypharmacy was 78.3%. According to the 2012 Beers criteria, 81.4% of patients received at least one PIM and 81.9% at the criteria of 2015. The main PIM prescribed were metoclopramide, ketoprofen and insulin. There was no association between prescription of MPIs and polypharmacy. Conclusion: There was a high frequency of use of PIM in the hospital. There were few differences in the prevalence of PIM when compared the versions 2012 and 2015 of Beers criteria. Studies on the use of drugs by elderly important tools in assessing the quality of health services provided to this population.