The prognosis of septicemic forms of early and late neonatal sepsis is severe with a high rate of mortality especially in premature infants. The evaluation of severity is difficult because of the non specificity of the clinical signs and mortality seems to be a good means of evaluation. A study was conducted in France on the mortality due to infection in neonatal intensive care units and neonatology wards during the third trimester 2000. Among 18 units, the mortality rate was 9.3% of admissions, corresponding to 11 early onset sepsis and 17 nosocomial infections. Death in primitive infections is essentially due to group B streptococci and E. coli with a more important risk in low gestational age infants. The nosocomial infections arise almost only in premature infant. Prognosis of infections due to Staphylococcus coagulase negative staphylococci, most frequent pathogens is good but mortalities rate is higher for enterobacteriacae--40% and for Pseudomonas, 62%.