Infection of the urinary tract is one of the most often seen urologic diseases. The clinical evaluation combined with blood and urine picture are enough for primary diagnosis and starting the treatment. Imaging is done if there is no desired response to the treatment. Early imaging is also preferred in patients with low immunity like old age patients or diabetics. Computed tomography (CT) is the preferred imaging technique for evaluating all types of pyelonephritis. The role of plain radiograph and intravenous urography (IVU) has been gradually declining in diagnosing urinary tract infection. A detailed discussion on the plain radiograph of kidney, ureter, and bladder, intravenous urography, micturating cystourethrography and retrograde urethrogram, ultrasonography, computed tomography, magnetic resonance imaging, and pathologies has been also provided in this chapter.