Survey period: Monday, May 21, through Saturday, June 23, 2001. The survey is conducted on a single day at each facility. However, depending on the size of the facilities and the number of surveyors available, the survey period may be spread over a week; the key point is that, for each department (or care unit), the survey must be conducted on a single day. In this case, care must be taken to conduct the survey on the same day in departments that regularly exchange patients, such as surgery and the intensive care unit of the same specialty. Finally, it is preferable to conduct the survey in the middle of the week (Tuesday or Thursday) to avoid periods when patient turnover is high. A questionnaire must be completed for each patient who is administratively present at the time the interviewer arrives in the department. The questionnaire will be completed regardless of whether the patient is present in the department, in the operating room, or undergoing a follow-up examination at the time of the surveyor’s visit. Day hospital beds as well as overnight hospital beds in CHSs will not be included in the survey. However, weekday inpatient units will be included. All inpatient units—whether for short-, medium-, or long-term stays—are included in the survey. Only nosocomial infections active on the day of the survey will be counted, that is, nosocomial infections for which systemic antimicrobial treatment has either not yet been initiated or is still ongoing. For nosocomial infections not requiring such treatment (local catheter-related infections, certain superficial surgical site infections, asymptomatic bacteriuria, etc.), recovery will be left to the discretion of the healthcare team. (R.A.)