We evaluated 100 children with normoblastemia and 400 control children in order to determine the significance of this finding in a pediatric population. None of the control children demonstrated nucleated erythrocytes (NRBC) in their peripheral blood. Among the 100 children with normoblastemia, 49% had underlying disorders associated with hypoxia. Only 8% of the children had malignancies. Eighty-eight percent of the patients in this study had obvious underlying disorders which accounted for their normoblastemia. However, those patients without an obvious etiology for their NRBC were at considerable risk for having bone marrow replacement.