The diagnostic significance of excretory urography, renal angiography, ultrasound and computed tomography for predicting the stage of tumours was evaluated by comparing their results with peroperative and histopathological findings. Thirty-nine out of 178 patients operated on for renal cell carcinoma from 1981 to 1988 were subjected to all four diagnostic procedures. The T stage was determined correctly by computed tomography in 80% of the cases, by ultrasound in 74.5%, by renal angiography in 64% and by excretory urography in 56.5%. Excretory urography did not give any significant additional information on the T category compared with the other imaging methods. Angiography is still of value in that it gives preoperative information on the collateral circulation and the number of renal arteries and their location.