Necrotizing pneumonia (NP) is a rare but complex complication of lobar pneumonia in children. It is characterized by massive necrosis and liquification of lung tissues by the presence of multiple cavities rather than a solitary one. To evaluate the clinical features of NP, we enrolled 17 patients at Chang-Gung Memorial Hospital (Kaohsiung) from November 1999 to December 2002. The diagnosis of NP was based upon findings of chest computed tomography. There were six boys and 11 girls, ages ranging from 47 days to seven years. Streptococcus pneumoniae was the most common pathogen responsible for 9 cases in our study. Our patients remained febrile, even with the appropriate antibiotics administered, for a mean of 12.1 +/- 5.2 days and hospitalized for a mean of 22.7 +/- 7.0 days. The right lung was affected more than the left (12:7). On admission, laboratory data showed either leukocytosis, or normal leukocyte count, or leukopenia, but C-reactive protein was abnormally high (mean = 304.8 +/- 96.3 mg/L). Anemia and significant platelet count elevation developed at a mean period of 8.5 +/- 3.5 and 10.9 +/- 4.7 days after their hospitalization, respectively. Surgical intervention was performed in one case only in our series. Chest roentgenography took a mean of 60.3 +/- 15.6 days to resolve completely. Although the clinical course was prolonged, all patients with NP eventually recovered completely with no sequela.