Introduction: Nosocomial infection or infection associated with care is a serious concern in intensive care units. It is a serious infection because of its frequency, incidence and additional cost. The objective of the study was to determine the epidemiological, clinical, therapeutic and evolutionary aspects of nosocomial infections in the intensive care unit of the regional hospital of Saint Louis. Materials and Methods: A one year retrospective, descriptive and analytical study of all cases of nosocomial infections found during the study period. We analyzed anamnestic, clinical, therapeutic, evolutionary and prognostic data. Results: 28 cases of nosocomial infections out of 243 hospitalized patients, an incidence of nosocomial infection of 11.5%. The mean age of the patients was 37.57 years with a standard deviation of 20.5 years. The reasons for admission were altered consciousness (28.5%), postoperative follow-up (21.4%), and acute respiratory failure (14.2%). Invasive procedures were represented by bladder catheterization (100%), central venous catheterization (64%), oro-tracheal intubation (39.2%), hemodynamic support (28.5%), extra-renal purification and parenteral nutritional support in respectively 10.7% and 7%. Pneumonia acquired under mechanical ventilation represented 28.5% of the infections identified, bacteremia 21%, urinary and neuro-meningeal infections 18% each and surgical site infections 14%. The germs identified were gram-negative bacilli (75%) (8 pseudomonas and 13 enterobacteria), gram-positive cocci in 25% of cases (5 staphylococci aureus Meti S and 2 staphylococci Meti R). The rate of microbial resistance was 35.7%. The average length of hospitalization was 16 days (Extreme = 60 -3 days). The mortality rate was 35%. Discussion/Conclusion: Nosocomial infections in the ICU are frequent and are associated with high morbidity and mortality. Effective preventive measures are the key to improve the prognosis.