This study examined individual and household socioeconomic status (SES) in relation to phenotypes of neural tube defects, orafacial clefts, and conotruncal heart defects using data from the National Birth Defects Prevention Study with 2,551 nonmalformed liveborn controls and 1,841 cases delivered in 1997-2000. The individual SES was measured by maternal and paternal education, occupation, and household income. All individual SES measures were combined to create a household SES index. Elevated risks were found for maternal low education in association with anencephaly and dextrotransposition of the great arteries (dTGA) (adjusted odds ratios (AORs) > or = 1.4); paternal low education in association with anencephaly, cleft palate, tetralogy of Fallot (TOF), and dTGA (AORs > or = 1.4); low household income in association with TOF (AOR = 1.4, 95% confidence interval (CI): 0.8, 2.5); maternal operator/laborer occupation in association with cleft palate, TOF, and dTGA (AORs > or = 1.4); paternal operator/laborer occupation in association with spina bifida (AOR = 1.4, 95% CI: 1.0, 2.0); and either parent's unemployment in association with dTGA (AOR > or = 1.4). Subjects with the lowest household SES index had the greatest risks of all selected birth defects except TOF. This study reveals consistently increased risks of selected birth defects in association with household SES index but not individual SES measures.