Nosocomial infections (NI) have achieved an increasingly large prevalence today, in Tunisia as well as abroad. Their on-going presence and occurrence are largely responsible for increasing morbidity and sometimes mortality. The aim of this work is to determine the prevalence of NI in the Kebili regional hospital and assess its level of impact. It consists of a cross-cutting study conducted in the Kebili regional hospital which holds 124 beds dispersed throughout 6 units. All of the patients hospitalised for more than 48 hours and who were present in the hospital between midnight February 17th to midnight February 18th, 2004, were included in the study. In the small hospital, 64 patients were present on the day of the study, 45 of whom had been already been hospitalised for over 48 hours. Among these 45, 6 patients (13%) tested positive for a NI. This prevalence is higher than that which is reported in the literature (2-3-9). The proportion of NI in this study is closer to that described in other series (2-7). In fact, we recorded the following : 2 cases of infection in the body zone operated upon (33%), 2 cases of urinary infection (33%), 1 case of pneumonia (17%), and 1 case of a skin infection (17%). The microbiological documentation, as it is described and presented in the other studies (1-7), was not found in our 6 patients here. The association and linkage between NI and certain other factors related to the provision of care has been documented as follows: surgical intervention, manipulations of the veins, gall bladder probing (or insertion of a catheter), tracheotomy, and prolonged hospitalisation (with an average stay of 16.5 days). The strong relationship between the occurrence of NI and the type of service or intervention administered during a hospital stay described in a select number of studies (2-5-7-11) does not present itself in our results. The overprescription of antibiotics among the patients in the hospital (52%) can be interpreted as a poor control mechanism and insufficient surveillance of the prescriptions and the delivery of these antibiotics, which serves as an important factor which contributes to NI and the development of resistance to available treatment. The work attempts to underline the importance of such a study on NI for the development and improvement of the quality of care, most importantly because the occurrence of NI constitutes a public health problem, and this is related to both the high prevalence of NI and its human and economic costs. In spite of the deficiencies noted in the clinical diagnoses and most notably the microbiological diagnoses, nosocomial infections are present in our hospital with a prevalence of 13%.