The application of the priniciples of linear tomography to enhance the visualization of the kidneys during excretory urography represents a major advancement in the quality of excretory urography. The ability to visualize the renal parenchyma and renal outlines on tomograms has resulted in a significant increase in the detection of renal masses, parenchymal scars, and adrenal tumors. The use of tomography may also contribute significantly to the evaluation of patients with various other urinary tract diseases. It has been our practice during the past 5 years to obtain linear tomograms as a routine procedure during excretory urography in all adults and in selected pediatric patients. We believe that tomograms of the kidneys represent an important part of the excretory urogram and should be done as a routine procedure.