Various species of Citrobacter may cause infections in neonates and immunocompromised hosts. Citrobacter koseri (formerly Citrobacter diversus) is best known as the cause of sepsis and meningitis leading to central nervous system (CNS) abscesses in neonates and young infants. Early onset and late-onset infections occur as for other neonatal bacterial infections. The majority of cases are sporadic, with no clear source of infection. A few have been confirmed to be vertically transmitted, and nosocomial outbreaks have occurred in neonatal care units. The pathophysiology is not well understood, but a surface protein has been identified as a possible virulence factor among strains that cause citrobacter brain abscesses in neonates. Despite improvements in diagnostic imaging techniques, surgery, and antibiotic therapy, approximately one-third of infants with abscesses die, and one-half sustain CNS damage. In this article, the taxonomy, epidemiology, pathogenesis, diagnosis, treatment, and outcome of citrobacter disease in children are reviewed.