Background: In 1998, the IOM recommended all women capable of becoming pregnant consume 400 mu g of folic acid daily to prevent neural tube defects (NTDs). Purpose: This paper aims to describe how different sources of folic acid contribute to achieving the recommended usual daily intake. Methods: Data on 2617 nonpregnant U.S. women aged 15-44 years from the 2003-2004 and 2005-2006 National Health and Nutrition Examination Surveys were analyzed in 2009. The usual daily folic acid intake from diet and supplements accounting for measurement error; the proportion of women consuming the recommended usual intake; and the adjusted associations of recommended intake with multiple characteristics were estimated. Results: Overall, 24% of nonpregnant U.S. women of childbearing age consumed the recommended usual intake (95% CI=20%, 27%). Intake was highest among non-Hispanic white women (30%), followed by Mexican-American (17%) and non-Hispanic black women (9%). Among women who used supplements with folic acid, 72% (95% CI=65%, 79%) consumed the recommended usual intake. Use of supplements was the strongest determinant (unadjusted prevalence ratio [PR]: 10.2, 95% CI=7.1, 14.7) of recommended intake, mediating associations of other characteristics. Among the 68% of women who did not use supplements, consumption of cereals with folic acid and having diabetes were the strongest determinants of recommended usual intake (PRs=20.2 and 0.10, respectively). Conclusions: Given that consumption of folic acid is an important public health goal to prevent NTDs, an evaluation of strategies, beyond recommendations that women consume supplements, is needed. (Am J Prey Med 2010;38(5):534-542) Published by Elsevier Inc. on behalf of American Journal of Preventive Medicine