We have recently shown that in premenopausal women without anaemia, glycated haemoglobin (HbA(1C)) is inversely associated with mean corpuscular haemoglobin (MCH). Based on the hypothesis that iron deficient state (IDS) due to menstruation may influence erythrocyte metabolism and thereby HbA(1C) levels, we examined the relation of iron metabolism indices with HbA(1C) in premenopausal women. HbA(1C), serum glycated albumin (GA) and iron metabolism indices were determined in 104 premenopausal women with normal glucose tolerance. Among them, 17 were diagnosed with iron deficiency anaemia (IDA) and 30 with IDS. The other 57 subjects were diagnosed with normal iron state (NIS). HbA(1C) levels showed significant inverse association with serum iron, serum transferrin saturation and serum ferritin in 104 study participants. Multivariate regression analysis identified serum ferritin as negatively associated with HbA(1C). These were also observed in 87 premenopausal women without IDA. HbA(1C) levels in IDA subjects and in IDS subjects were higher than it in NIS subjects, while GA levels were not different among the three groups of subjects. In conclusions, iron metabolism indices influence HbA(1C) levels, but not serum GA levels, in premenopausal women.