Purpose: The Scientific Studies Committee of the Surgical Infection Society undertook the present study to examine the prevalence of and indications for antimicrobial use in intensive care units where members of the Society practice. Methods: Information and data collection sheets were posted on the Internet for download by members interested in participating. All centers were required to obtain approval from their local human subjects research office or equivalent. A one-week time was set during which the center could collect information on any one day, at the center's convenience. Data collection sheets were then sent to the lead author for analysis. Seventeen centers reported data for 371 patients in 22 intensive care units. Results: Trauma and general surgical patients comprised 224 of the patients (60%). The indications for anti-infective agents were prophylactic (22%), empiric (27%), therapeutic with known pathogen (41%), therapeutic without known pathogen (e.g., cellulitis) (4%), insistence of influential practitioner (4%), or non-anti-infective purposes (e.g., erythromycin for gastric motility) (2%). Only 44%, 29%, and 54% of the orders for prophylactic, empiric, and therapeutic antibiotics, respectively, had date-certain stop dates. The antimicrobial drugs most commonly used were vancomycin, piperacillin-tazobactam, and fluconazole. Conclusion: Most patients were receiving antimicrobial agents. Polypharmacy was common. Most patients did not have a date-certain stop date. This study sets the benchmark for future study regarding antibiotic prescribing behavior in surgical intensive care units.