Urinary tract infection is the most common complication after kidney transplant and often is associated with graft loss and mortality. Ultrasonography is the most widely applied imaging modality for diagnosis of complications after kidney transplant. Here, we report a case of a 52-year-old male patient who underwent renal transplant 1 month earlier and who presented with fever, leukocytosis, and leukocyturia. Klebsiella pneumoniae was found in the urine and blood cultures. Ultrasonography revealed multiple, ill-defined margined, hypoechoic areas and cysts within the cortex. Both clinical findings and ultrasonography findings were resolved after antimicrobial therapy. One month later, the patient presented again with fatigue, leukocytosis, and leukocyturia. Blood and urine culture results were consistent with Klebsiella pneumoniae. Ultrasonography revealed large hypoechoic mass, including multiple cysts in the upper pole of the transplanted kidney. Doppler ultrasonography showed increased vascularity within the hypoechoic mass and surrounding parenchyma. Renal parenchymal echogenicity was also increased in the upper pole. Ultrasonography-guided percutaneous drainage was performed. Clinical, laboratory, and ultrasonography findings were resolved after antimicrobial therapy. Ultrasonography plays an important role in the diagnosis and evaluation of the treatment response of urinary tract infections after kidney transplant.