The aim of the study was to determine the prevalence rate and risk factors relevant to neural tube defects (NTDs) in Turkey. All live births and stillbirths recorded at the university hospitals throughout Turkey between July 1993-June 1994 were evaluated with respect to congenital anomalies. For each birth, information was recorded about the child, the mother, the pregnancy and risk factors. A total of 66 cases with a NTD were recorded in 21,907 births. Prevalence rate of NTDs was 30.1 per 10,000 births. Of these 66 cases, 29 (43.9%) were male and 37 (56.1%) female. Female/male ratio was 1.27. The ratio of spina bifida/anencephaly is 1.20 for Turkey. Maternal illiteracy, maternal advanced age and residence in northern or eastern regions of Turkey are shown to be risk factors for having a baby with a NTD. The prevalence rate of NTDs is very high for Turkey. Geographical distribution of NTDs in this country confirms a relationship between the socioeconomic status and environmental factors for the development of a NTD. The results of this study point to the importance establishing a health policy to prevent neural tube defects in Turkey.