The number of pregnancies affected by neural tube defects has been estimated to be 4000/year in Europe, with a higher prevalence in Celtic populations and in women of low socioeconomic status. Since the 1980s, it has been shown that supplementation with folic acid during the periconceptual period reduces the risk of neural tube defects in the fetus. However, in view of the period during which supplementation should be taken (< 4 weeks before conception until 8-10 weeks after) and the fact that in some countries 30-50% of pregnancies are unplanned, a public health initiative based solely on increasing dietary folate intake or recommendations on use of folic acid supplements is likely to be insufficient. Mandatory fortification has been started in 38 countries throughout the world. Several European countries have advocated mandatory flour folic acid fortification over the last 6 years, but none has introduced it. A recent public health decision in Hungary stimulated flour fortification on a voluntary basis, but it remains the only European country to take this action. Many European countries have deferred a decision to introduce fortification because of concerns about possible masking of vitamin B (12) deficiency. This review advocates a proposal for combined fortification of folic acid and vitamin B (12) to address possible hazards of fortification with folic acid alone.