To estimate the incidence of nosocomial infections (NI) in our hospital and to increase healthcare professionals' awareness of hygiene, a prospective study was performed between January and December 2002 from the microbiology laboratory data. On 1334 suspicions of NI, corresponding to 1062 patients, sent to the hygiene correspondents in each medical care unit, the infection control team received 853 answers (64% of sendings) with 430 NI validated. The incidence rate of NI validated was 1.7 NI/1000 days of hospitalisation and 1.6 NI/100 inpatients. The NI were predominantly related to urinary tract (47%), bloodstream (14%), and lower respiratory tract (12%). Transmission of these informations to medical information department permitted a valorisation of additional 16,000 ISA points. This prospective study permitted to develop a network of hygiene correspondents in every medical care units. None of the medical care units was unharmed by NI but the exhaustive declaration of NI seems difficult to realise. This study permitted to point out some dysfunctionments in the management of invasive procedures and to improve these practices.