A study was carried out to investigate the errors involved in obtaining volumes by means of ultrasound echograms and a small computer. The work was done on live pigs' kidneys (130-200 cm3). The errors include those associated with the scanner itself, those invloved in the interpretation of the contour boundaries, and those relating to the algorithms used to determine the volumes from the contours. An average deviation of 25.4 cm3 from actual volumes was found, while 58% of the measurements were within +/-10%. Computer programs allowing for the display of contours and intercepts of corresponding orthogonal scan planes were used to reanalyze the data resulting in an average deviation of 14.7 cm3 with 78% of the data resulting inan average deviation of 14.7 cm3 with 78% of the measurements with "/-10%.