A one-day point prevalence study to investigate the patterns of antibiotic use was undertaken in 43 latin American (LA) intensive care units. Of 510 patients admitted, 231 received antibiotic treatment on the day of the study (45%); in 125 cases (54%) due to nosocomial-acquired infections. The most frequent infection reported was nosocomial pneumonia (43%). Only in 122 patients (53%) were cultures performed before starting antibiotic treatment. 33% of the isolated microorganisms were enterobacteriaceae (40% extended-spectrum beta-lactamase-producing), 23% methicillin-resistant Staphylococcus aureus and 17% carbapenems-resistant non-fermentative Gram-negatives. The antibiotics most frequently prescribed were carbapenems (99/231, 43%); alone (60/99, 60%) or in combination with vancomycin (39/99, 40%). "Restricted" antibiotics (carbapenems, vancomycin, piperacillin-tazobactam, broad-spectrum cephalosporins, tigecycline, polymixins and linezolid) were most frequently indicated in severely ill patients (APACHE II score at admission >15, p=0.0007 and, SOFA score at the beginning of the antibiotic treatment >3, p=0.0000). Only 36% of antibiotic treatments were cultured-directed.Our findings help explain the high rates of multidrug-resistant pathogens in LA settings (i.e. ESBL-producing Gram-negatives) and the severity of the registered patients illnesses.