Bacterial infections remain an important cause of neonatal mortality and morbidity. Pathogenesis of the neonate's predilection to infection are multifactorial. Factors directly attributable to the infant include humoral, phagocytic, and cellular deficiencies. Septic neonates may have reduced neutrophil storage pools that cause profound neutropenia. Both correlate with poor prognosis. Antibiotic administration is mandatory in neonatal sepsis. Supplementary treatments may be useful. Granulocyte transfusions, when available, provide neutrophils, improving the neonate's neutrophil count and neutrophil function. The efficacy of intravenous immunoglobulin (i.v.IG) is questionable because the prophylactic and therapeutic administration of i.v.IG fails to reduce the incidence of bacterial infections or affect the overall survival rate. Hyperimmune preparations seem to be more effective. The administration of granulocyte colony-stimulating factor induces myeloid progenitor proliferation, enhances the neutrophil storage pool, produces neutrophilia, and improves neutrophil function. More extensive, well-designed, and carefully control trials are needed to determine the benefit of supportive therapies for neonatal sepsis.