Healthcare-associated infections are more common in intensive care units than in other areas of care due to the critical condition of patients and the invasive nature of life-support techniques. Surveillance in these units is essential for quantifying the risk of infection, monitoring its progression, and identifying prevention strategies. In France, network-based surveillance of healthcare-associated infections in intensive care units began at the interregional level as early as 1994. Thanks to the standardization of surveillance methodologies within the Raisin framework, this network became national in 2004, with coordination entrusted to CClin Sud-Est. This surveillance focuses on infections associated with invasive devices (“device-related”), for which prevention is a priority. The incidence rate of these infections per 1,000 days of exposure to risk is the preferred indicator: it provides the best measure of their frequency of occurrence and allows for comparisons between units. This report presents the first French national data from network-based surveillance of the incidence of nosocomial infections in adult intensive care. From January 1 to June 30, 2004, 133 intensive care units in France voluntarily participated in the REA-Raisin surveillance program, continuously collecting data over a 6-month period on 16,566 patients hospitalized for more than 2 days in intensive care. The level of infection risk must be interpreted in light of various risk factors considered in the surveillance, particularly those related to the patient: age (mean age of 62 years), sex (male-to-female ratio of 1.64), diagnostic category (internal medicine 64%, emergency surgery 17%, and elective surgery 19%), trauma status (10%), immunosuppression (13%), patient origin (external 59%, short-stay 32%, medium- and long-stay 6%, other ICU 3%), presence of antibiotic therapy at admission (48%), severity score (mean IGS II of 38.5), and finally length of stay (average of 11 days). The use of invasive devices must also be considered: intubation (58.4% of exposed patients), central venous catheterization (55.6%), or urinary catheterization (79.8%); the influence of the duration of exposure to these devices was taken into account. Among the 16,566 patients monitored, 2,335 patients (14.1%) developed at least one infection (or colonization in the case of central catheters), for a total of 3,710 infections/colonizations. For all departments combined, the observed incidence rates were as follows: 17.39 pneumonia cases per 1,000 days of intubation, 6.10 colonizations per 1,000 days of central venous catheterization, 3.23 bacteremias per 1,000 days of intensive care hospitalization, and 8.3 urinary tract infections per 1,000 days of catheterization. The characteristics of the intensive care units were highly heterogeneous (size, equipment, organization, practices, staffing), which partly explains the significant inter-unit variation in the observed incidence rates. Comparing them requires optimal adjustment of the indicators based on the use of "patient" risk factors, even if collecting this data increases the workload. This report provides an initial overview that enhances understanding of the risk of nosocomial infection in intensive care. It will serve as a reference and enable the optimization of risk control through the provision of feedback on the results to intensive care physicians. Annual analysis of these data will ultimately allow for the evaluation of the impact of the preventive measures implemented by the participating units. (R.A.)