Fulfilling a nosocomial infection watch program in a neurosurgery department lead to assess the basic situation i.e. the same characteristics related to both surgery and I.C.U. (incidence rate of wound infections 3%, of bronchopulmonary tract infections 20.8% and of urinary tract infections 9.1%). To ensure feasibility of data collection and data accuracy, strategy was based on weekly passive epidemiological data collection, laboratory data and monthly confrontation with neurosurgery's practitioners.