The ultrasonic appearances of the kidney in images which contain grey shades corresponding to the detected echo-pulse heights have been examined. These "greyscale" images were obtained using a standard Nuclear Enterprises Diasonograph 4102B and a Varian 620/L digital computer interfaced to this Diasonograph. The computer was used to analyse and display the ultrasonograms with 16 grey shades. Both kidneys of 36 subjects were examined and compared with IVU findings. This group included patients with normal kidneys, polycystic kidneys, hydronephrosis, glomerulonephritis and neoplastic tumours. It was found possible to make sharp, grey-shaded ultrasonograms which were very useful to the diagnostician. In particular, the grey shade of the renal parenchyma was used as a standard to compare other grey-shaded structures. Also the grey shading was useful in defining the renal pelvis in transverse scans and the renal poles in axial scan.