Iron deficiency anemia (IDA) is one of the most serious forms of malnutrition. A promo-tion function of mineral absorption has been reported for neutral oligosaccharides, but not acidic xylooligosaccharide (U-XOS), which is a novel oligosaccharide. We hypothe-sized that U-XOS could promote recovery from IDA by enhancing the serum iron level. Therefore, the aim of this study was to investigate whether or not U-XOS was useful for recovery from IDA in the rat. Twenty-four female Sprague-Dawley rats were randomly divided into a control group fed a control diet (4.0 mg Fe /100 g) and an IDA model group created by employing a low-iron diet (0.4 mg Fe /100 g). The IDA group was further di-vided into three subgroups on day 21: U-XOS-supplemented diet (LI-X, 4.0 mg Fe /100 g), low-iron diet (LI), and control diet (LI-C) groups. No significant differences in the serum iron transferrin saturation levels were demonstrated between the control and LI-X groups on days 26 and 35. The divalent metal transporter 1 and ferroportin mRNA expression levels shown in the first segment of the small intestines showed a significant decrease in the LI-X group, compared with the LI group. A significant decrease in the hepatic hep-cidin mRNA expression level and iron content was also demonstrated in the LI-X group, compared with the control group, but not compared with the LI group. These results sug-gested that U-XOS could promote recovery from IDA by enhancing serum iron at an early stage of the recovery process.