Abstract: Objective To understand the prevalence of birth defects in Shaanxi province, and to provide scientific evidence for the study of its risk factors.Methods Stratified random cluster sampling method was adopted.Overall 124 towns were sampled from 9 cities and 12 counties in Shaanxi province.There were 13 273 women enrolled in the home investigation and all of these women had 28 weeks' gestational age from October 2007 to July 2009.Results The prevalence of birth defect in Shaanxi province was 141.6 per 10000.The first five main birth defects were skin abnormality (43.7/10000), congenital heart disease(21.8/10000), central nervous system and neural tube defect(17.3/10000), cleft lip (3.8/10000), and dysmelia (3.8/10000), followed by accessory auricle deformities (3.8/10000), inguinal hernia (3.0/10000), cerebral palsy (3.0/10000), and blepharoptosis(3.0/10000).Conclusion The prevalence of birth defect in Shaanxi province was higher than the national average level in 2004.The major types of birth defect changed greatly compared to that in 2000.The prevalence of skin abnormality is the highest and the prevalence central nervous system and neural tube defect is in the third place.