Objectives: To analyze the point prevalence of antimicrobial agent use by older adults and to determine the quality of use in a teaching hospital. A pharmacoepidemiological, observational study. Methods: Retrospective collection of clinical, microbiological and pharmacotherapeutic data in medical records. Inclusion criteria: age ≥ 60 years old, in use of one or more antimicrobial agents. The resistant microorganisms classified as priority pathogens by the World Health Organization (WHO) were identified. The quality of antimicrobial agent use according to quality indicators described by Van den Bosch et al. (2015) was determined. A descriptive statistical analysis was performed. Results: Of the 130 hospitalized older adult individuals, 40.8% were using one or more antimicrobials agents on the day of point prevalence. Among the 50 resistant microorganisms identified in the cultures, 54.0% corresponded to pathogens of critical priority. Antibiotic glycopeptides (14.9%) and penicillins associated with beta-lactamase inhibitors (13.8%) were the most prescribed classes of antimicrobial agents. The Quality Indicators (QIs) of antimicrobial therapy demonstrated more frequent inadequacy regarding therapeutic monitoring, sequential therapy and blood culture request. Conclusions: The prevalence of antimicrobial agent use in older adults was high. Empirical therapy is often developed in line with that advocated by the Infection Control Commission. The high isolation of critical pathogens according to the WHO, evidences the importance of actions to ensure the rational use of drugs in the institution. The QIs demonstrated the need to implement guidelines for systematizing therapeutic antimicrobial agent monitoring in the institution and educational action on the process of requesting blood cultures.