BACKGROUND: Emphysematous pyelonephritis (EPN) is a severe gas-forming infection of renal parenchyma with high mortality and its adequate treatment modality remains controversial. There have been only a limited number of studies about EPN, particularly in Korea. Therefore, we present our experience in patients with EPN. MATERIALS AND METHODS: Twenty-four patients that were diagnosed with EPN between January 1999 and June 2010 at a single medical center were retrospectively evaluated. Patient characteristics, causative pathogens, clinical features, complications, and mortality rates as modalities of managements and radiological classes of EPN were analyzed. RESULTS: All of the 24 patients selected for the study were diabetic. Twenty-one patients were positive at urine culture and Escherichia coli (85.7%) was the predominant pathogen identified. Of the 24 patients, 17 were managed by broad-spectrum antibiotics and percutaneous renal drainage, whereas 7 were managed by direct nephrectomy. The total mortality rates were 12.5%, regardless of the modalities of management. The mortality rates were 12.5% in Class 3A and 40% in Class 3B, according to computed tomography (CT) findings. CONCLUSIONS: Although conservative treatment included antibiotics, and percutaneous renal drainage offered an effective therapy for EPN, nephrectomy should be considered in patients with Class 3 EPN.