Introduction. Efforts to understand the burden of antibiotic use in low- and middle-income countries such as Brazil are essential for developing strategies that are effective and appropriate in the context of endemic multidrug-resistant organisms.Aim. This study aims to determine antimicrobial-prescribing practices among patients hospitalized in intensive care units (ICUs) for adults in Brazil.Methodology. A 1-day point prevalence multicentre survey was conducted in 58 adult ICUs across the five regions of Brazil. The institutions were categorized according to their type and size. Detailed antimicrobial prescription data were prospectively provided to all patients hospitalized on the day of data collection.Results. A total of 620 patients were included in the study, of whom 63.9% were receiving at least one antimicrobial. Of these, 34.6% were treated for an infection, but only 39.9% of the cases were based on microbiological criteria. Empirical treatment was applied to 72.3% of the patients. Significant differences in antibiotic usage were observed across the different hospitals included in the study. Overall, treatment was most commonly directed towards pneumonia (51.8%) and bloodstream infections (29.6%). Glycopeptides (19.4%) and carbapenems (18.5%) were the most prescribed in teaching hospitals, while in non-teaching hospitals, carbapenems (17.8%) and broad-spectrum cephalosporins (16.8%) were most frequently used.Conclusion. Our study reveals alarming data on antibiotic use in adult ICUs in Brazil, with high frequencies of severe healthcare-associated infections acquired in these units, where patients are frequently subjected to empirical treatment.