We studied 157 pregnant women living in Merida, Spain, during their third trimester of pregnancy and their newborns at birth, analyzing the mother's and the umbilical cord's blood for hemoglobin, hematocrit, mean corpuscular hemoglobin concentration (MCHC), serum iron and serum ferritin. We observed statistically significant correlations between hemoglobin and hematocrit values of the mother with erythrocyte count, hemoglobin and hematocrit values of her child and between serum iron of mother and child. The blood levels in the umbilical cord did not decrease until the ferritin value of the mother was < 12 μg/1. Under these conditions the ferritin levels in the umbilical cord blood (80.4 μg/1) were significantly lower than in those newborn infants whose mother had adequate ferritin levels (123 μg/1). We deduce that maternal iron status seems to condition, at least partially, fetal iron status, specially when the mother has some deficiencies. We did not find a lower birth weight in children of anemic mothers. Actually, we found an inverse correlation between maternal hemoglobin values and infant birth weight (r =-0.1731, p < 0.05). It is possible that the demands on the mother are increased in the case of a newborn infant of greater size.