Each year in the United States, approximately 4000 pregnancies are affected by spina bifida and anencephaly. Babies born with spina bifida usually survive, often with serious disability, but anencephaly is invariably fatal. The B vitamin folic acid can reduce the occurrence of spina bifida and anencephaly by at least 50% when consumed daily before conception and during early pregnancy. In 1992, the Public Health Service (PHS) recommended that all women of childbearing age who are capable of becoming pregnant consume 400 microg of folic acid daily. Folic acid can be obtained from multivitamins or certain other supplements and from some fortified breakfast cereals. It is found naturally in orange juice, green leafy vegetables, and beans; however, it is difficult to obtain the recommended 400 microg daily through diet alone. This report summarizes findings from a survey conducted during January and February 1997 that indicate modest increases since 1995 in knowledge about and consumption of folic acid among U.S. women aged 18-45 years and highlights the need for additional public health efforts to take full advantage of this prevention opportunity.