Objective: The aim of this study was to determine the level of knowledge and use of periconceptional folic acid supplementation in a sample of postpartum women recruited from three hospitals. Design: Cross-sectional survey in which a structured questionnaire was used in a face-to-face encounter between the subject and a trained nurse. Settings: Two teaching hospitals associated with Faculty of Medicine and Health Sciences and one private hospital. Subjects: Postpartum women in the three hospitals were recruited during a 40-day period in November 1999. Women who did not agree to participate, had complicated labor, delivered babies with congenital malformations, or were too exhausted or difficult to examine, were excluded. Results: Univariate analyses showed that overall 46.4% of the respondents had heard about folic acid and only 8.7% knew that it prevented birth defects. 45.5% of respondents took folic acid in the first trimester. The percentage of women who had ever heard about folic acid was higher in those with higher education, and those who were not UAE nationals. Use of folic acid was associated with non-UAE nationality. Conclusion: Awareness of the value of periconceptional folic acid was very low and use of folic acid was less prevalent among women of UAE nationality. (C) 2002 Elsevier Science Inc. All rights reserved.