Periconceptional folic acid supplementation is effective in the prevention of neural tube defects (NTDs). The aim of the present study was to determine the level of knowledge about the benefits of preconceptional folic acid supplementation in a sample of women of childbearing age and its associated factors. A cross-sectional community-based study design was carried out on a total of 441 women of childbearing age. Questionnaires included knowledge of preconception of folic acid supplements and socio-demographic characteristics. The χ2 was used to compare categorical data. Multivariate logistic regression was used to isolate the predictive variables and examined individually by calculating the adjusted odds ratio. Statistical significance is declared as P < 0·05. We found that 35·1 % (n 155) knew preconceptional folic acid supplementation could prevent NTDs, and 3·8 % (n 17) knew the right time to take preconceptional folic acid supplementation and only 1·7 % (n 7) who had a history of NTDs. Attended secondary education (OR 2·7; 95 % CI 1·1, 6·0, P = 0·017), governmental employee (OR 3·5; 95 % CI 2·3, 17·8, P < 0·001), current pregnancy status (OR 3·0; 95 % CI 2·1, 4·2, P = 0·043), history of visiting the antenatal care service during pregnancy (OR 2·9; 95 % CI 1·07, 7·8, P = 0·03), history of taking folic acid supplement (OR 4·5; 95 % CI 2·9, 7·1, P < 0·001) were associated. More than half of the participant women did not know about preconception of folic acid supplements that reduce the risk of NTDs. Identification of the level of knowledge on preconception of folic acid may allow for targeted educational or other interventions to further encourage folic acid use.