Background: Folic acid can prevent up to 70% of neural tube defects (NTDs) if taken before pregnancy. Compared with other race-ethnicities, Hispanic women have higher rates of NTDs, lower rates of folic acid supplement use, and lower total folic acid intakes. Objective: The objective was to assess potential effects of fortifying corn masa flour with folic acid on Mexican American women and other segments of the US population. Design: A model was developed by using data from the National Health and Nutrition Examination Survey 2001-2004 to estimate the folic acid content in foods containing corn masa flour if fortified at a level of 140 ug folic acid/100 g corn masa flour. Results: Had corn masa flour fortification occurred, we estimated that Mexican American women aged 15-44 y could have increased their total usual daily folic acid intake by 19.9% and non-Hispanic white women by 4.2%. Among the US population, estimated relative percentage increases in total usual daily folic acid intake with corn masa flour fortification were greatest among Mexican Americans (16.8%) and lowest among children aged 1-3 y (2%) and adults aged >51 y (0-0.5%). Conclusion: Analyses suggest that corn masa flour fortification would have effectively targeted Mexican Americans, specifically, Mexican American women, without substantially increasing folic acid intake among other segments of the population. Such increases could reduce the disparity in total folic acid intake between Mexican American and non-Hispanic white women of childbearing age and implies that an additional NTD preventive benefit would be observed for Mexican American women.