The article presents case study of a 29-year-old female who was hospitalized with right-flank pain and pyrexia. She had delivered a healthy baby 2 weeks ago. Urinalysis of the woman showed pyuria and microscopic hematuria, and urine culture revealed Klebsiella pneumoniae-extended-spectrum b-lactamase strain. Postpartum renal abscess was confirmed on the basis of clinical findings and radiological examinations.