Objectives. To describe the microbiological and therapeutic characteristics of confirmed neonatal sepsis, and determine its incidence and mortality, at the National Hospital Arzobispo Loayza (HNAL) from 2011 to 2012, Lima, Peru. Materials and Methods. Retrospective longitudinal study. It was performed a monitoring to newborns with probable sepsis, and assessed the results from positive blood cultures. The newborns' characteristics were obtained from medical records. The acumulated incidences of confirmed sepsis, mortality and fatality rates were determined. Quantitative variables were reported as men ± standard deviation or median (interquartile range). Qualitative variables were reported as relative frequencies and percentages. Results. The incidence of confirmed sepsis was 4.1 per 1 000 live births (95% confidence interval [CI]: 2.7-5.5). The mortality rate was 0.97 per 1 000 live births (95% CI: 0.29-1.63) and the fatality rate was 23.5% (95% CI: 9-37). The most commonly isolated organism was coagulase-negative Staphylococcus, followed by Staphylococcus aureus, both with high rates of oxacillin resistance (90% and 66.6%, respectively). A 67% of the newborns were treated using ampicillin/amikacin or ampicillin/cefotaxime. Antibiotics were changed in 58% of the newborns because of poor clinical/laboratory evolution or blood culture results. In most cases the seconds antibiotic was vancomycin (42.8%). Conclusions. There is a high incidence of confirmed sepsis and a high fatality rate. The administered treatments were not consistent with the microbiological profiles.