Necrotizing pneumonia causes necrosis of pulmonary parenchyma and may lead to pulmonary gangrene. Prior ti the antibiotic era, extensive pulmonary involvement was potentially fatal, but the incidence of necrotizing pneumonia is now less common. On contrast-enhanced CT scans, consolidation with contrast enhancement containing necrotic foci with low attenuation and cavities is characteristic. Radiologic findings do not differ according to the causative organism and in most of cases, specific diagnosis may be impossible. Clinical findings and certain characteristics radiologic findings may be helpful for narrowing the differential diagnosis. We illustrate the clinical and radiologic characteristics of necrotizing pneumonia according to causative bacterial organisms.