The practical result borne by our investigations has been the introduction of routine estimation of cord blood total protein. In every case when the concentration is below the 10 percentile value, the clinicians are warned. Further catamnestic studies are needed to judge the values of cord blood cholesterol estimations in screening for familial hyperlipoproteinemias. The hypercholeterolemic infants of the present series, who are 2-3 years old at present, as well as their families must be subjected to repeat analysis. The change in opposite directions of cord blood total protein and cholesterol levels with the advance of gestation was a remarkable finding. This correlation indicates a close interaction between protein and lipid metabolism. Less promising results have been obtained in investigations of the cord blood calcium and magnesium levels, but final conclusions can only be drawn after repeat analyses. Introduction of the routine estimation of these two parameters does not seem necessary at present. Besides clinical data, biochemical parameters have also been found suitable for differentiating small-for-date infants from true prematures. The functional maturity of these infants was shown by the fact that their different cord blood components were normal.