Hepatic portal venous gas (HPVG) became more easily diagnosed after the advent of abdominal computed tomography scan in the emergency department. However, the clinical significance of HPVG is popularly discussed; and its etiology remains uncertain. In this report, we present a 49- year-old diabetic, hemodialytic woman who presented with afebrile flank pain and a significant HPVG detected on abdominal computed tomography, which implied a unilateral perirenal abscess (so-called emphysematous pyelonephritis). This patient received percutaneous drainage and antibiotics therapy without emergency laparotomy intervention. No evidence of existing mesenteric infarction or bowel obstruction was detected during admission, and the patient was discharged with an uneventful outcome. To our knowledge, this is the first case of HPVG that originated from emphysematous pyelonephritis and was treated by successful emergency drainage.