The ministerial decree of July 26, 2001, requires the reporting of healthcare-associated infections (HAIs), the procedures for which were specified in the circular of July 30, 2001, and subsequently in that of January 22, 2004. Cases of HAI meeting the external reporting criteria set forth in the aforementioned documents must be reported to the Interregional Coordination Centers for the Control of Healthcare-Associated Infections (CClin) and to the health authorities (Ddass). This system, whose primary objective is to provide an early warning, is intended to identify situations involving "risks of transmission (of the HAI) to third parties, or the emergence or spread of similar cases," which should trigger appropriate preventive actions. The local Operational Hygiene Team (EOH) is on the front lines to conduct investigations and implement corrective and preventive measures, with the potential assistance of the CClin. The reasons for and the impact in terms of action or prevention of reports received since August 2001 are highly diverse. Assessing the specificity of a report is difficult in the absence of a precise definition of the ideal report. To better understand the specificity of reports, the authors examined the relevance of reports received by the CClin over an 18-month period, focusing on the severity of the reported incidents and their impact in terms of preventive actions. (Authors’ Introduction)