Purpose : To analyze CT and follow-up chest radiographic findings in patients with necrotizing pneumonia andto evaluate clinical significance of the extent of necrosis. Materials and Methods : We reviewed medical recordsand retrospectively analysed CT scans and follow-up chest radiographs of 22 patients with necrotizing pneumonia,confirmed by biopsy(n=7) and culture(n=15). Inclusion criteria for necrotizing pneumonia was necrotic lowattenuation, with or without cavitation on postcontrast enhanced CT scan. The study group included 15 men andseven women, aged 11-66 years (average:47years). Results : The pathogens of necrotizing pneumonia were Klebsiellaspp(n=7), Enterobacter spp(n=5), Actinomyces spp(n=4), Pseudomonas spp(n=4), Nocardia spp(n=4), and others(n=5).Average duration of pneumonia was 4.1 months. On CT scan, pneumonic consolidations were well-marginated in 14patients and there were cavities on initial CT scan in 16 cases. Margins of the necrotic portion on CT scan werewell-demarcated in majority of the patients(16/22). Low attenuation areas on initial CT scan resulted incavitation, fibrosis and volume loss as shown on follow-up chest radiographs. The larger the necrotic areas on CT,the more the volume loss was. Conclusion : CT findings of necrotizing pneumonia were well-marginated air-spaceconsolidation with low attenuation area, with or without cavity. The extent of necrotic area was closely relatedwith the degree of fibrotic change later on. CT is important tool for diagnosis and prediction of parenchymaldamage in necrotizing pneumonia.