Prolonged courses of broad-spectrum antibiotics are often cited as the standard of care for prevention of infective complications of open fractures. The origins of these recommendations are obscure, however, and multi-drug-resistant systemic infections attributable to antibiotic overuse are common life-threatening problems in current intensive care unit practice. To review systematically the effects of prophylactic antibiotic administration on the incidence of infections complicating open fractures. Computerized bibliographic search of published research and citation review of relevant articles. All published clinical trials claiming to evaluate, or cited elsewhere as being authoritative regarding, the role of antibiotics in open fracture management were identified and then evaluated according to published guidelines for evidence-based medicine. Only small studies (<20 patients), practice surveys, pharmacokinetic studies, and reviews or duplicative publications presenting primary data already considered were excluded from analysis. Information on demographics, study dates, fracture grade, antibiotic type, duration and route of administration, surgical interventions, infection-related outcomes, and the methodologic quality of the studies was extracted by the authors. The primary results were submitted to the Therapeutic Agents Committee of the Surgical Infection Society for review prior to creation of the final consensus document. Current antibiotic management of open fractures is based on a small number of studies that generally are more than 30 years old and do not reflect current management priorities in trauma and critical care. With a few noteworthy exceptions, these primary studies suffer from a variety of methodologic problems, including co-mingling of prospective and retrospective data sets, absence of or inappropriate statistical analysis, lack of blinding, or failure of randomization. The data support the conclusion that a short course of first-generation cephalosporins, begun as soon as possible after injury, significantly lowers the risk of infection when used in combination with prompt, modern orthopedic fracture wound management. There is insufficient evidence to support other common management practices, such as prolonged courses or repeated short courses of antibiotics, the use of antibiotic coverage extending to gram-negative bacilli or clostridial species, or the use of local antibiotic therapies such as beads. Large, randomized, blinded trials are needed to prove or disprove the value of these traditional approaches. Such trials should be performed in patients with high-grade fractures who (1) are well-stratified according to the degree of local injury and (2) undergo standardized fracture and wound management. Trials also must be powered to study the effects of extended antibiotic coverage on nosocomial infections. Antibiotic regimens confirmed to improve local fracture outcomes in such studies could then be used rationally, balancing the risks of local fracture-related infections and of multi-drug-resistant systemic infections to achieve optimal global outcomes.