The periconceptional intake of folic acid supplements reduces risk of neural tube defects by 40 – 70%. Although the Ministry of Health and Welfare recommended the intake of folic acid 0.4mg for those planning to conceive in 2000, the prevalence of myelomeningocele has not decreased. We aim to investigate proportion of dietitians who are aware of preventive effects of folic acid and to compare the data with those identified in two previous questionnaire studies. Questionnaires were sent to 200 registered dietitians and 35% or 70 of the dietitians responded. It is revealed that 75.7% of them were aware of preventive effects of folic acid and that 37.1% and 87.1% recommended folic acid supplementation and well-balanced diet, respectively. Transmission of information on folic acid to the people was supported by 92.9%, and abstain from smoking and alcohol were recommended by 78.6% and 75.7% of them, respectively. Thirteen percent of dietitians were aware that women of the high risk group were necessary to take folic acid ten times as much as ordinary women take. Awareness of preventive effects of folic acid among dietitians significantly elevated to 75.7% compared with that studied 10 or 15 years ago (p<0.01). The amount of dietary folate adults women take is approximately 240 ㎍ per day, which is not sufficiently enough to prevent the occurrence of neural tube defects. Consequently, registered dietitians should frequently recommend taking folic acid supplements.