Dynamic computed tomography and angio-tomography combine criteria generated by CT with those of angiography and are advocated by the author to improve staging of renal cell carcinoma. Dynamic CT was performed in 29 patients and angio-CT in 12 patients in this group. Rapid acquisition of data permits generation of a CT section in intervals of 1 to 6 seconds, which in turn reflects arterial, capillary, and venous transit of contrast medium through tissues. The propensity for dense enhancement of renal cell carcinoma makes possible positive identification of tumor elements. This feature proved accurate for the assessment of local extension of renal neoplasms in all 29 patients, involvement of the renal vein by tumor in 9/10, involvement of the inferior vena cava by tumor in 6/6, and involvement of regional nodes by tumor in 6/8.