In the intensive care unit (ICU), our sickest patients receive our most invasive treatments and are therefore highly vulnerable to hospital-acquired infection. Up to one-third of ICU patients develop infectious complications of care, with associated increases in morbidity, mortality, and healthcare costs. Earlier research has indicated substantial heterogeneity in uptake of infection prevention best practices in North American hospitals, and this variability may also exist in ICUs. We hypothesized that ICU system-level characteristics, including closed model of care, academic affiliation, and availability of a dedicated infection control practitioner (ICP), may be associated with improved infection prevention practices.During July 2011, we conducted a province-wide survey of nurse directors in ICUs across Ontario, Canada (population, 12 million). We developed a 77-item questionnaire to broadly capture ICU structures and processes relevant to infection prevention. The questionnaire was developed (item generation and reduction) by the authors and was further improved through pilot and sensibility testing by 3 ICU nurse directors and 2 ICPs. It was then distributed via e-mail by the Ontario Ministry of Health and Long-Term Care Critical Care Secretariat to nurse directors of all ICUs. A second email was sent to nonrespondents 2 weeks later. Approval was granted by the research ethics board at Sunnybrook Health Sciences Centre in Toronto, Canada.