Pneumonia is the leading cause of death in children around the world. This article reviews the clinical manifestations, diagnoses, and management of the major causes of bacterial pneumonia in children of different ages. Major pathogens causing pneumonia in newborns include group B streptococcus, Listeria monocytogenes , and Chlamydia trachomatis , organisms that can infect infants born to mothers who have genital tract colonization. Streptococcus pneumoniae remains the most common cause of serious bacterial pneumonia in children, and the increasing incidence of penicillin-resistant strains can complicate therapy. Mycoplasma pneumoniae and Chlamydia pneumoniae are the most common causes of pneumonia in school-aged children. In most cases of bacterial pneumonia, a specific cause is not determined, and empiric therapy is based on the likely pathogens as determined by the child's age and the clinical presentation. Prevention, through simple measures such as breast-feeding and avoidance of exposure to passive smoke, as well as widespread use of available vaccines, is the most effective means of reducing the morbidity and mortality associated with bacterial pneumonia.