This book provides an extensive account on neonatal bacterial infection. Neonatal sepsis is still a considerable cause of disease and mortality in the newborn, specifically in preterm, low birth weight infants. In spite of progresses in neonatal care, all over case-fatality rates from sepsis may be as much as 50%. Clinical signs of bacterial infection are unclear and non-specific, and up to now there is no readily available, reliable marker of infection regardless of a huge bulk of analyses focused on inflammatory indices in neonatology. All neonatologists confront the confusion of under or over diagnosing bacterial infection. This book primarily elucidates topics which are: clinical description covering a basic approach to sepsis neonatorum, two different diagnoses pneumonia and osteomyelitis diagnostic approaches encompassing C-reactive protein and the immature myeloid information, and treatment as well as prevention of bacterial infection with immunoglobulins.