Two hundred human term placentas underwent morphometric study by means of semiautomated computerized method. Outer villous perimeter per cent parenchymal area and mean chord length were the investigated parameters. The mean value of outer villous perimeter, mean chord length and per cent area were respectively 46.9 mu (X 1000 mu 2) with a standard deviation of 4.6, 57.7 mu (standard deviation 9.3) and 66.1% (standard deviation 7.4). The relative distribution of these various parameters can constitute a valid basis for a comparison in cases of placental insufficiency.