Women of childbearing age are advised to consume folic acid-containing supplements. Whether this remains necessary after folic acid fortification of the food supply in North America has yet to be determined. The objectives of this study were to assess folate intakes and the contribution of folic acid to the diets of women of childbearing age in the post-folic acid fortification era. Using a cross-sectional study design, fasting blood samples were obtained from 95 women (aged 18 to 25 years), and the samples were analyzed for serum and red blood cell folate, as well for total homocysteine. Dietary and supplemental folate intakes were assessed. The biochemical evidence showed that no women were folate deficient, but only 14% reached red blood cell folate concentrations associated with significant reductions in neural tube defect risk. Mean dietary intake of food folic acid was 96+/-64 microg/day, supplemental folic acid was 94+/-189 microg/day, natural folate was 314+/-134 microg/day, and the total intake, as dietary folate equivalents, was 646+/-368 microg dietary folate equivalents/day. Therefore, intakes of folic acid from fortified foods are within the level originally predicted for the fortification efforts; however, only 17% of participants met the special recommendation for women capable of becoming pregnant (400 microg folic acid daily from supplements, fortified foods, or both in addition to consuming food folate from a varied diet). These data suggest that women of childbearing age are achieving positive folate status in the postfortification era, but it may not be sufficient to achieve red blood cell folate concentrations associated with a significant reduction in neural tube defect risk. Even with food fortification, women of childbearing age should be advised to take a folic acid-containing supplement on a daily basis.