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Background & Objective: Neural tube defects (NTDs) are a heterogenous group of malformation which is resulting from failure of normal neural tube closure between the 3rd and 4th week of embryonic development. The most common form of this malformation is anencephaly, spinabifida and ancephalocele. Prevalence of this malformation differs from geographic situation and race distribution. Materials & Methods: The aim of this study was to determine the prevalence and risk factors of NTDs in Birjand Hospital between 1996 to 2000. After diagnose of malformation among the 16785 infants born in the 2 hospitals in Birjand, reliable questionnaire was completed for the mothers who had malformed infants. The data was analyzed by SPSS software. Results: Prevalence of NTDs was 2.97 per 1000 birth, more higher than other countries anencephaly and spina bifida is common form of NTDs in this area. Consanguinity, previous abortion, malformed childbirth, malformed child in the family, diseases during pregnancy and winter delivery were some of the risk factors. Most of the mother (96%) didn’t take the Folic Acid during their pregnancy. Conclusion: The findings from this study indicate that the rate of NTD in Birjand is relatively higher comparing to other studies in different countries. Further investigations are recommended to find out the etiology of NTD in this area.