Diabetes mellitus has a number of long-term effects on the genitourinary system. These effects predispose to bacterial urinary tract infections in the patient with diabetes mellitus. Bacteriuria is more common in diabetic women than in nondiabetic women because of a combination of host and local risk factors. Upper tract infection complications are also more common in this group. Diabetic patients are at higher risk for intrarenal abscess, with a spectrum of disease ranging from acute focal bacterial pyelonephritis to renal corticomedullary abscess, to the renal carbuncle. A number of uncommon complicated urinary tract infection complications occur more frequently in diabetics, such as emphysematous pyelonephritis and emphysematous pyelitis. Because of the frequency and severity of urinary tract infection in diabetic patients, prompt diagnosis and early therapy is warranted. A plain abdominal radiograph is recommended as a minimum radiographic screening tool in the patient with diabetes presenting with systemic signs of urinary tract infection. Ultrasonography or further radiographic studies such as CT scanning may also be warranted, depending on the clinical picture, to identify upper urinary tract complications early for appropriate intervention.