This study was designed to observe iron status and prevalence of iron deficient conditions in adult female habitual runners (n=111) and inactive females of comparable age (n=65). The runners were significantly lower (p<.05) than the reference group in mean serum ferritin (SF), total iron binding capacity, and red blood cell count, but significantly higher (p<.05) in mean corpuscular hemoglobin. The groups did not differ significantly in hemoglobin concentration, hematocrit, serum iron, percent saturation of transfenin, or red cell protoporphyrin. Chi square analysis indicated that iron depletion (SF <20 ng·ml-1) was significantly more prevalent (p<.005) in the runners than in the controls. Anemia was extremely rare in both groups. A multiple regression analysis revealed significant negative associations between serum ferritin and coffeeltea intake (p<.001) and running activity (p<.05). These results indicate that habitual runners, as compared with inactive women, are at increased risk for iron deficient states but that full-blown anemia is a rare consequence of this deficient iron status.