OBJECTIVE We examined the dietary intake and the use of supplements of folic acid (FA) in a cohort of pregnant women. We also explored the factors associated with non-compliance of both the recommended intake (RI) of 600 μg/day and the supplement use of 400 μg/day provided to prevent neural tube defects (NTD). METHODS We studied 782 pregnant women from the INMA-Valencia cohort. The dietary intake was estimated using a food frequency questionnaire in two periods of pregnancy; from preconception to the second month and from the 3rd to the 7th month. Information on supplement use was also collected which allowed us to estimate the total FA intake (diet+supplements). We explored factors associated with non-compliance of the recommendations by logistic regression. RESULTS The periconceptional mean daily FA intake was 304 μg/day. FA supplements were taken by 19.2, 30.2 and 66.2% of women in preconception, first and second month of pregnancy, respectively. Among women using supplements in periconception, 30% exceeded the tolerable upper intake level (UL) of 1.000 μg/day. Non-compliance with RI was more common among women of foreign origin, of low educational level, who smoked, with unplanned pregnancy, who did not visit a private gynaecologist, who had had children or without previous medical illness. CONCLUSIONS Diet by itself is not sufficient to reach RI for FA during pregnancy and many women initiate supplement use after the recommended period and inadequately. The youngest women, with lowest educational attainment and unplanned pregnancies are more likely not to comply.