Hb A_1 and Hb A_<1C> in cases with iron deficiency anemia (I.D.A.) and in controls were measured by high-performance liquid cnromatography. The mean and S.D. levels of these in three hundred and sixty-seven normal subjects were 7.0±0.8% and 4.7±0.6%, respectively. Hb A_1 in cases with I.D.A. (7.7%) was significantly higher than that in controls (p<0.05); however, in Hb Alc components, there was no difference between anemic patients and controls. Furthermore, there was no significant correlation between Hb A_1 and Hb A_<1c> in patients with I.D.A.. From these results, we suspected that other components excluding the Hb A_<1c> in Hb A_1 fraction, such as Hb A_<1a+b> and/or Hb F and so on, might relatively increase in patients with I.D.A..