Glycated fractions of hemoglobin F and A (F1, A1c) were measured simultaneously in cord and maternal blood, respectively, in 109 normal women at delivery using an isoelectric focusing, method in polyacrylamide gel plates. Cord blood hemoglobin F1 values (mean +/- SD) were 5.92 +/- 1.09% and maternal blood hemoglobin A1c values were 6.51 +/- 0.92%. The difference was statistically highly significant (p less than 0.001) and their values were also significantly correlated (p less than 0.001). Moreover, both values were also well correlated with those of maternal blood glucose (p less than 0.01), actual birth weight (p less than 0.01) and birth weight ratio (p less than 0.01). It is concluded that hemoglobin F1 can be successfully separated and measured by isoelectric focusing. However HbF1 estimation seems to have no obvious advantages against the maternal HbA1c measurement as an index of fetal exposure to glucose during the last weeks of pregnancy.