The risk of smoking during pregnancy in the US is strongly associated with women's individual socioeconomic status (SES) but little is known about the influence of local area context. The aim of this study was to examine whether local-area characteristics increase the risk of smoking during pregnancy above and beyond individual SES. In a hospital-based cohort of 878 pregnant women in California, who delivered between 1980 and 1990, we compared risk of smoking during pregnancy based on individual and local-area factors. Adjusting for individual SES, neighborhood social class was related to smoking in early pregnancy. Living in a predominantly working-class area significantly increased the risk of pregnancy smoking for both working-class and non-working-class women. However, local-area economic and demographic indicators were not related to smoking early in pregnancy. Individual and family characteristics alone may be insufficient to explain smoking during pregnancy; the social class context of the places in which pregnant women live may also influence this behavior.