Surveillance networks for nosocomial bacteremia have been gradually established by the C. CLINs since 1994 (C. CLIN Sud-Est, C. CLIN Paris-Nord) to facilitate hospitals’ surveillance of this nosocomial infection, which is responsible for a significant number of deaths. Participation in these networks enables hospitals to adopt a common methodology for data collection and analysis. This surveillance of nosocomial bacteremia (NB) is one of the components of the minimum surveillance program for nosocomial infections recommended since 1992 by the National Technical Committee on Nosocomial Infections (CTIN). An initial harmonization of methods and procedures for reporting results began among the networks at the initiative of the C. CLINs and the CTIN. The data presented are from four interregional networks coordinated by the C. CLINs and the network of the Centre region. The results are for the year 2000 for the C. CLINs East, Southeast, Paris-North, and the Centre regional network, and for the year 1999 for the C. CLIN Southwest. (R.A.).