This experiment is designed for bone health in wrestlers and martial arts athletes who lose weight with Rapid Weight Loss (RWL). To clarify the effect of iron intake on the relationship between weight loss and bone densityFor athletes using the RWL strategy, iron intake was observed for bone mineral density (BMD), serum osteocalcin (OC) level, and serum iron marker. This study was conducted on 23 wrestlers (13 males and 10 females). It was divided into the trial 1 (iron intake and weight loss) and the trial 2 (only weight loss). In addition, between the first and second experiments, a washout period was given for 3 weeks} in order to eliminate the medicinal effect. All measurements were performed in the same group. However, the OC levels were reduced following RWL. In case of the males, the intake group after weight loss demonstrated a significant increase in BMD (p<0.05). Correlation analysis of the data for the male group showed significant correlations between serum OC and iron contents (p<0.05), total BMD and TIBC(total iron binding capacity) (p<0.05), and transferrin and iron concentrations (p<0.05). In the female group, serum OC and iron (p<0.01), transferrin and TIBC(total iron binding capacity) (p<0.01) showed correlations. In addition, between serum OC and ferritin (p<0.05), total BMD and ferritin (p<0.05), TIBC and iron (p<0.05) were shown to have some degree of correlation in the global evaluations.