Neonatal sepsis is a clinical syndrome characterized by systemic signs and symptoms, and bacteremia during the first month of life. The incidence is relatively low (one to eight cases/1000 live births), yet the risk of mortality is approximately 25%. Meningitis in the neonate is usually a sequela of bacteremia; however, it is discussed with neonatal sepsis, because they commonly share etiology and pathogenesis. The incidence of meningitis is usually a fraction of the number of infants with sepsis, varying in different settings from one-fourth to one-third. The mortality rate is high, varying in some series from 15%-50%. There are two major forms of presentation of neonatal sepsis. Early-onset disease presents as a fulminant, multisystemic illness during the first 5-7 days of life; late-onset disease is more commonly recognized after the first weeks of life. Because different microorganisms are responsible for the two forms of disease, the choice of antimicrobial agents also differs. Some organisms such as Escherichia coli, group B streptococci, and Listeria monocytogenes may be responsible, whereas other pathogens such as Staphylococcus aureus and S. epidermidis, and Pseudomonas aeruginosa are usually associated with late-onset disease. Classic initial (empiric) treatment of neonatal sepsis and meningitis consists of ampicillin and an aminoglycoside. With the advent of the third-generation cephalosporins, however, the empiric antimicrobial approach for neonatal sepsis and meningitis has changed in most centers. Third-generation cephalosporins cover more of the pathogens implicated in neonatal sepsis and meningitis, except for the enterococci and L. monocytogenes. In the Fourth Neonatal Meningitis Collaborative Study, neonates were assigned to receive saline or dexamethasone before parenteral cefotaxime and ampicillin. The preliminary data from 37 neonates from six Latin American countries show a low mortality rate and no side effects attributable to the study drugs.