Egypt has a high incidence of neural tube defects. Folic acid supplementation in the periconceptional period is known to lower the risk of such defects. This cross-sectional study aimed to measure the level of knowledge about periconceptional folic acid use among pregnant women attending for antenatal care at Ain Shams University Hospital, Cairo, Egypt in 2012. Questionnaires were filled through personal interviews with 660 pregnant women. Of the respondents, 62.4% had heard of folic acid and 39.2% knew about the role of folic acid supplementation in prevention of congenital anomalies. Knowledge about using folic acid before and in the first trimester of pregnancy was highest among university-educated women and those working in professional occupations. Only 18.8% of women reported taking folic acid, and 8.8% had used it before conception. Awareness campaigns are suggested to improve knowledge about folic acid among women in the childbearing period in Egypt.