Kokuto-moromi vinegar (KMV) was prepared by freeze-drying the supernatant that was obtained after the centrifugation of the post-distilled slurry. The bioavailability of iron in the KMV was evaluated in the iron deficient rats   The iron deficient group was fed on the iron deficient diet, and the KMV group was fed the diet that was added the freeze dried KMV. The iron content in the KMV diet was equivalent to the iron content in AIN-93 mineral mixture in the control diet.   In the iron deficient group, the body weight gain, total iron content of liver and blood, hemoglobin, ferritin and hematocrit values were lower, and values unsaturated iron binding capacity (UIBC), total iron binding capacity (TIBC) values were higher than those in the control and KMV groups.   The body weight gain, total iron contents of liver and blood, hemoglobin, ferritin, hematocrit values, UIBC and TIBC were recovered to the same levels of the control diet group by adding the KMV to the iron deficient diet.   These results indicate that the iron KMV is efficiently absorbed by iron deficient rats.