The aim of this study was to evaluate the number of deaths associated with nosocomial infections (NI) and the contribution of these NI to death. A multicentre descriptive study was conducted in 16 tertiary-care hospitals (14 222 beds) in Northern France. Medical records of consecutive patients who died at least 48 h after admission were reviewed for cause of death, NI and disease severity, before admission and before NI onset. The contribution of NI to death was assessed by agreement between two physicians according to a three-category scale of probability. Among the 1945 patients who died during the study, 26.6% had an NI. According to the agreed diagnosis, NI contributed to the deaths of 284 (14.6%) patients(certainly for 6.6% and possibly for 8%), thereby ranking NI as the fourth most frequent cause of death. Considering the deaths that had not been anticipated independently of NI two weeks before they occurred, NI definitely contributed to 2.8% of them. Lower respiratory tract, bloodstream and surgical wound infections were responsible for 39, 20 and 14%, respectively,of all NI in these patients. The impact of NI on in-hospital mortality seems to be lower than had previously been estimated in France based on US data from the 1970s and 1980s. To improve healthcare quality, further studies are needed to elucidate the processes that may contribute to fatal severe NI.