CONTEXT AND OBJECTIVE: Smoking during pregnancy is an important risk factor for maternal and infant health that is preventable. This study aimed to investigate the risk factors associated with smoking behavior during pregnancy. DESIGN AND SETTING: A household-based probability sample survey of 1,510 women was conducted in the center of the city of Sivas, Turkey, between September 2013 and May 2014. METHODS: The prevalence of smoking during pregnancy was estimated according to independent variables by means of regression analysis. RESULTS: The prevalence of smoking during pregnancy was 16.5%. Logistic regression showed that being at a relatively young age (odds ratio, OR = 1.92, P = 0.025 for 15-24 age group; and OR = 2.45, P = 0.001 for 25-34 age group), having a low educational level (OR = 1.76, P = 0.032), being unmarried (OR = 1.48, P = 0.002) and living in an extended family (OR = 1.98, P = 0.009) were the factors associated with the risk of smoking during pregnancy. CONCLUSIONS: Systematic attention should be paid to socioeconomic inequalities, to support women towards quitting smoking before or at an early stage of their pregnancies. Younger women and particularly those in lower socioeconomic groups should be targeted. This will lead to better pregnancy status, especially among young women.