Emphysematous pyelonephritis is an uncommon and life-threatening necrotizing infection of the renal parenchyma that requires prompt diagnosis and early treatment. It is associated with gas-forming coliform bacteria, and is characterized by the presence of gas within the renal parenchyma. The clinical picture and gas pattern should be monitored carefully before a surgical desion is made. If there is persistence of gas on serial x-rays despite aggressive therapy, prompt surgical therapy is recommended. We herein present 1 diabetic patient with emphysematous pyelonephritis who responded to medical treatment alone. The presence of gas was confirmed by CT scan and Escherchia coli was isolated in both urine and blood cultures. The patient was treated with antibiotics alone. Although the clinical signs and laboratory findings were improved, intrarenal gas persistently appeared over 1 month. CT scan 2 month after medical treatment revealed absence of gas in the renal parenchyma.