The purpose of this research is to assess th iron nutritional status of pregnant women and to evaluate the appropriateness of the present cut off levels of hemoglobin(Hgb), hematocrit(Hct) and total iron binding capacity(TIBC) for assessing iron deficiency status. Pregnant women who were visiting public helath centers in Ulsan were interviewed and agreed to attend the study. Blood sample was taken and biochemical analysis of blood was performed. The collected data were classified into 3 trimesters by gestational age and then statistical analysis was performed. The prevalence of anemia in all subjects was 32.3% by WHO criteria(Hgb < 11.0g/dl) and 17.8% of all subjects was iron deficient anemia by CDC criteria(Hgb < 11.0/dl and serum ferritin < 12.0ug/l). Since the iron deficient anemia generally occures at the last stage of iron deficiency, it is not efficient to diagnose and prevent the iron deficient anemia in pregnant women by using the present cut off level of Hgb. Therefore, the new cut off level of iron status indices is necessary for assessing iron deficiency in early pregnancy before manifestation of anemia and for reducing the prevalence of anemia in later pregnancy. For this reason, the present cut off levels of iron status indices were estimated and compared by assessing the iron deficiency judged by serum ferritin level (<12.0ug/l)as true iron deficiency. It follows from the results of this research that present cut off levels of Hgb, Hct and TIBC were very insensitive in identifying the subjection with iron deficiency. The appropriate cut off levels of Hgb were 11.5g/dl for total period of pregnancy, 12.0g/dl for 1st and 3rd trimester, and 11.5g/dl for 2nd trimester. The cut off level of Hct was 34.0% for total period for pregnancy, 35.0% for 1st trimester, and 34.0% for 2nd and 3rd trimester. The cut off level of TIBC was 400ug/dl for total period, 360ug/dl for 1st 2nd trimester, and 450ug/dl for 3rd trimester.