Folic acid is one of B group vitamins (B9 vitamin). It is water soluble. In food it is found in reduced form as pteroilglutamic acid, in folate form, and in supplements comes as pteroilmonoglutamic acid. Folates have multiple roles in organism. They are responsible for the normal cell differentiation and participate in synthesis of great number of different cells. They are also necessary for the proper brain functioning, mental and emotional health, play role in control of the homocysteine level and in metabolism and energy generation. Folic acid is especially important in pregnancy because its deficiency can cause miscarriages and congenital anomalies. The two most common birth defects of the brain and spine are spina bifida and anencephaly. These neural tube defects occur when part of the neural tube, which later develops into spinal cord and brain, does not close. Closing normally happens around 24th day after the conception, before a woman realises she is pregnant. Results of the studies have shown that the periconceptional use of supplements with folic acid alone, or multivitamins combined with folic acid, can lower the risk of neural tube defects by 40% up to 80%. Also, more effective prevention of neural tube defects could be achieved by initiation of food fortification with folic acid because daily requirements are usually not satisfied only by food intake. In the absence of mandatory fortification, national campaigns to increase knowledge and use of folic acid among women should be intensified and adequately funded. Obstetricians, paediatricians, and general practitioners can play an important part in informing and motivating women to take folic acid supplements preconception.