The applications of three-dimensional (3D) CT techniques encompass a spectrum from calculus disease to preoperative planning. With proper selection of display windows and levels, accurate measurement of stone size can be achieved, along with volumetric information. A CT scan with reconstruction may help guide the direction of an endopyelotomy incision away from crossing vessels. The benefits of 3D CT in the evaluation of living renal donors include lower cost and decreased patient morbidity. In renal allograft recipients and other patients, the study may be used to investigate hypertension. Also, 3D CT is invaluable in planning nephron-sparing surgery for renal masses. The ultimate role of this modality rests in the hands of clinicians who can benefit from them and the radiologists who must provide the high-quality images and the interpretive expertise.