The present study aimed to investigate how nutritional status affected iron status, and how this knowledge might be used to prevent anemia in rhythmic gymnasts prior to a competition. We divided twenty-one subjects according to their iron status in just prior to competition into either an iron-deficiency group (n=12) and a non-iron-deficiency group (n=9), the latter of which represented the normal group. Iron-deficiency group was defined as a hemoglobin concentration below 12g/dl, a ferritin level below 12ng/ml and/or a transferrin saturation ratio under 16%. Physical, hematological, and nutritional assessments were made using a semi-quantitative food frequency questionnaire, once at 2 months before a competition, and once more just prior to the competition (‘pre-competition’).1) The iron-deficiency group had significantly lower body weight, body mass index and body fat at pre-competition compared to 2 months before the competition.2) Compared to the normal group, the iron-deficiency group had significantly lower serum iron and haptoglobin concentrations at the pre-competition.3) Intakes of energy, protein, iron, and vitamin C at the pre-competition were 1965±340kcal, 68.0±14.0g, 11.2±3.2mg, and 76±30mg in the normal group, and 1620±456kcal, 53.8±18.0g, 11.6±4.1mg, and 75±29mg in the iron-deficiency group, respectively. There was no significant difference in intakes of energy, protein, iron, and vitamin C between the groups, respectively.4) Pre-competition protein intakes per body weight (BW) were 1.46±0.33g and 1.08±0.31g in the normal group and the iron-deficiency group, respectively. Those levels were significantly lower in the iron-deficiency group than those in the normal group.5) Pre-competition protein energy ratio (13.9±1.6%) and animal protein ratio (56.0±6.7%) of the normal group were significantly higher than those measured 2 months before the competition. Conversely, those ratios remained constant for 2 months in the iron-deficiency group.6) Changes in the protein energy ratio and/or the animal protein ratio between the pre-competition and the 2 months before were significantly correlated with the pre-competition Hb levels.We conclude that the pre-competition iron status is closely associated with protein intakes in female collegiate rhythmic gymnasts.